Analyst
PAPER
Blood and breath levels of selected volatile organic
compounds in healthy volunteers
Cite this: Analyst, 2013, 138, 2134
Pawe1 Mochalski,*ab Julian King,a Martin Klieber,ac Karl Unterkofler,a
Hartmann Hinterhuber,d Matthias Baumanne and Anton Amann*ac
Gas chromatography with mass spectrometric detection (GC-MS) was used to identify and quantify volatile
organic compounds in the blood and breath of healthy individuals. Blood and breath volatiles were preconcentrated using headspace solid phase micro-extraction (HS-SPME) and needle trap devices (NTDs),
respectively. The study involved a group of 28 healthy test subjects and resulted in the quantification of
a total of 74 compounds in both types of samples. The concentrations of the species under study varied
between 0.01 and 6700 nmol L
1
in blood and between 0.02 and 2500 ppb in exhaled air. Limits of
detection (LOD) ranged from 0.01 to 270 nmol L
1
for blood compounds and from 0.01 to 0.7 ppb for
breath species. Relative standard deviations for both measurement regimes varied from 1.5 to 14%. The
predominant chemical classes among the compounds quantified were hydrocarbons (24), ketones (10),
Received 27th November 2012
Accepted 1st February 2013
terpenes (8), heterocyclic compounds (7) and aromatic compounds (7). Twelve analytes were found to
be highly present in both blood and exhaled air (with incidence rates higher than 80%) and for 32
species significant differences (Wilcoxon signed-rank test) between room air and exhaled breath were
DOI: 10.1039/c3an36756h
observed. By comparing blood, room air and breath levels in parallel, a tentative classification of
www.rsc.org/analyst
volatiles into endogenous and exogenous compounds can be achieved.
1
Introduction
Analysis of exhaled air has great potential for medical diagnosis
and therapeutic monitoring.1–4 It offers a unique and noninvasive method for tracking biomarkers originating from
normal biochemical processes as well as from pathological
disorders. For instance, alkanes and methylated alkanes proved
to be useful in distinguishing lung cancer patients from healthy
controls,1,5–8 for recognizing heart rejection aer transplantation,9 breast cancer,10 or for the detection of oxidative
stress.11,12 A major prerequisite for the successful application of
breath tests is the assumption that a robust correlation between
the blood and breath levels of analytes of interest can be
established. Unfortunately, the origin and metabolic fate of
numerous breath species have not been elucidated in sufficient
depth, thereby limiting the clinical application of breath tests.
In this context, the identication of blood-borne breath
a
Breath Research Institute, Austrian Academy of Sciences, Rathausplatz 4, A-6850
Dornbirn, Austria. E-mail: pawel.mochalski@i.edu.pl; anton.amann@i-med.ac.at;
Fax: +43-512-504-6724636; Tel: +43-512-504-24636
b
Institute of Nuclear Physics PAN, Radzikowskiego 152, PL-31342 Kraków, Poland
c
Univ.-Clinic for Anesthesia, Innsbruck Medical University, Anichstr, 35, A-6020
Innsbruck, Austria
d
Univ.-Clinic for Psychiatry, Innsbruck Medical University, Anichstr, 35, A-6020
Innsbruck, Austria
e
Univ.-Clinic for Pediatrics I, Innsbruck Medical University, Anichstr. 35, A-6020
Innsbruck, Austria
2134 | Analyst, 2013, 138, 2134–2145
constituents and species resulting from exogenous sources (e.g.,
environmental exposure) as well as the understanding of their
physiological levels in human tissues and uids is of fundamental importance.
Recently, volatile organic compounds forming human scent
have received special attention in the eld of safety and security,
as they are potential markers of human presence during Urban
Search and Rescue (USaR) operations organized aer natural or
man-made disasters (e.g. earthquakes, explosions and terrorist
attacks).13–17 Breath, next to skin, is a principal source of human
scent constituents. Contrary to some temporal sources like
blood or urine, it offers long-lasting emission of VOCs. This is
due to the fact that a trapped victim has to breathe and, thereby,
breath constituents can help to discriminate between living
humans and corpses. Nevertheless, the role of blood or urine
VOCs in the vicinity of victims should not be underestimated.
Bearing in mind that earthquake victims are frequently severely
injured,18 it becomes clear that blood is an important reservoir
of scent VOCs. In this context, knowledge of the human scent
prole and the contribution of particular sources in the scent
pool is critical.
While the quantitative analysis of breath constituents has
received widespread attention,5,19–22 relatively few studies have
investigated the levels of these volatiles in human blood.
Moreover, the majority of studies investigating blood VOCs were
focused on selected classes of species (e.g. toxic or carcinogenic
substances), or dealt with specic groups of individuals (e.g.,
This journal is ª The Royal Society of Chemistry 2013
Paper
smokers, mechanically ventilated patients, or subjects exposed
to predened amounts of contaminants). A number of studies
investigated the blood levels of halogenated hydrocarbons and
aromatics (BTEXS) as biomarkers of environmental exposure.23–27 In non-occupational exposure settings Perbellini
et al.28 reported blood and breath levels of 1,3-butadiene,
benzene and 2,5-dimethyl furan. The blood levels of smokingrelated species were analyzed, e.g., by Houeto et al.29 and
Chambers et al.30 In the eld of breath gas analysis Miekisch
et al.31 investigated the blood concentrations of isoprene,
dimethylsulde, n-pentane and isourane in mechanically
ventilated patients and the blood concentrations of propofol in
patients under anesthesia.32 A particular focus has also been on
isoprene. O'Hara et al. reported breath and blood levels of
isoprene (and acetone) in volunteers during re-breathing,33,34
Cailleux et al.35 provided its blood abundances in spontaneously
breathing test subjects and King et al.36 determined the
isoprene concentrations in the blood and breath of muscle
dystrophy patients. Regarding aldehydes, blood hexanal and
heptanal were determined by several authors as potential
biomarkers of lung cancer.37,38
Due to the above-mentioned lack of studies measuring
breath and blood levels of VOCs in parallel, the primary goal of
this work was the quantication of the widest possible range of
volatile organic compounds in both types of samples. In
particular, by this we also intended to provide a comprehensive
list of reliable reference concentration values for healthy
volunteers as well as to tentatively classify the observed species
into systemic/exogenous compounds by comparing their absolute concentrations in blood, breath, and room air. A secondary
goal was to create a library of potential blood-borne and breathborne markers of human presence. Gas chromatography with
mass spectrometric detection was employed as the analytical
method for the determination of breath and blood constituents.
2
Experimental
2.1
Materials and calibration mixtures
Gaseous and liquid multi-compound calibration mixtures were
prepared from pure liquid or gaseous substances. The reference
substances with purities ranging from 90–99% were purchased
from Sigma-Aldrich (Austria), Fluka (Switzerland), ChemSampCo (USA), Acros Organic (Belgium) and SAFC (USA).
The preparation of the gaseous calibration mixtures was
dependent on the compound's volatility and solubility in water.
Mixtures of less volatile and well soluble species were produced
by means of a GasLab calibration mixtures generator (Breitfuss
Messtechnik, Germany). The GasLab unit consists of an integrated zero air generator, a 2-stage dynamic injection module
for evaporating a liquid and diluting it with zero air, and a
humidication module enabling the preparation of gas
mixtures at well-dened humidity levels (up to 100% relative
humidity (RH) at 37 C). When using the pure liquid substances
GasLab is able to produce a ow of up to 10 L min 1 of complex
trace gas mixtures diluted in dry or humidied zero air containing from 10 ppb to 100 ppm of each solute. However, for the
goals of this study, pure substances were additionally diluted
This journal is ª The Royal Society of Chemistry 2013
Analyst
(1 : 2000–1 : 3000) with distilled water prior to evaporation in
order to reduce the resulting concentration levels. Effectively,
humid gas mixtures (80% RH at 37 C) with volume fractions
ranging from approximately 0.02 to 1000 ppb were used during
calibration and validation.
Multi-compound standards of poorly soluble and very volatile compounds (mainly hydrocarbons) were prepared in a
distinct manner. In a rst step, primary standards were
prepared in 1 L glass bulbs (Supelco, Canada). Before usage,
each bulb was thoroughly cleaned with methanol and dried at
70 C for at least 12 h to remove potential contaminants. Then,
the bulb was evacuated using a vacuum membrane pump and
approximately 1–2 mL of liquid (or 0.5–1 mL of gaseous) analyte
was injected through a rubber septum. Next, the bulb was
heated to 60 C for 30 min to ensure complete evaporation and
subsequently pressure was balanced to ambient levels with
high-purity nitrogen (6.0–99.9999%). The nal calibration
mixtures were prepared by transferring appropriate volumes of
the primary standard into Tedlar bags lled with predened
amounts of humidied zero air (80% RH at 37 C), the latter
again being produced by the GasLab generator.
To mimic the composition of real breath samples all calibration mixtures additionally contained 100 ppb of isoprene
and 800 ppb of acetone. For each compound, breath calibration
curves were obtained on the basis of 3-fold analyses of 7 distinct
and independently prepared concentration levels.
Blood species were calibrated using human plasma
samples.31,34 The latter were obtained from centrifuged heparinized whole blood (CS-6R Centrifuge, Beckman, USA) transferred into glass vials and frozen at 20 C immediately aer
centrifugation. Defrosting was performed at room temperature
directly before the calibration measurements. For the purpose of
reducing background signals all plasma samples were conditioned prior to the standard mixture preparation. This was
achieved by stirring the samples at room temperature and under
vacuum conditions.34 Calibration solutions were prepared in two
steps. For the majority of species primary solutions were
produced by adding 1–200 mL (depending on the analyte solubility and desired blood concentration range) of pure liquid
substance into 250–500 mL of distilled water (M00 200 system,
Modulab, Austria), followed by intensive stirring for 20 minutes
at 24 C. If very low concentration levels (below 1 nmol L 1) were
targeted the primary solution was additionally diluted with water
at a ratio of 1 : 100. The nal calibration solutions were prepared
by transferring appropriate aliquots of primary solutions into
crimped vials containing 2.7 mL of plasma and 0.3 mL of Dulbecco's PBS (PAA Laboratories, Austria).
The blood calibration solutions of very volatile compounds
poorly soluble in blood (mainly hydrocarbons) were prepared
with the help of glass bulbs (Supelco, Canada). In a rst step,
primary gaseous mixtures were prepared in analogy to the
calibration of very volatile breath compounds as described
before. Next, these primary standards were diluted with
nitrogen at a ratio of 1 : 200–1 : 300 using an additional glass
bulb. Finally, crimped vials containing conditioned plasma
samples were spiked with appropriate volumes of the diluted
gaseous mixture using gas-tight syringes (Hamilton,
Analyst, 2013, 138, 2134–2145 | 2135
Analyst
Switzerland). Finally, blood volatiles were calibrated against
plasma calibration solutions covering concentration ranges
from 0.01 to 9000 nmol L 1, depending on the substance under
scrutiny.
2.2
Human subjects and sampling
A cohort of 28 healthy volunteers (14 males, 14 females, age
range 18–54 years, median age 32.5 years, 6 smokers) was
recruited. All subjects gave written informed consent to participate. The blood and breath collection was approved by the
Ethics Commission of Innsbruck Medical University. No special
dietary regimes were applied, however, volunteers were asked to
rest for at least 10 min before sampling to avoid temporal
breath VOC concentration changes related to exercise.39–42 In
addition, prior to the sampling step all individuals had been
staying in the room atmosphere for at least one hour. During
this time, volunteers completed a questionnaire describing
their health and smoking status, as well as recent food intake.
For each volunteer venous blood was sampled twice from the
median cubital vein using BD Valu-Sets (BD, UK) and MultiAdapters (Sarstedt, Germany) into 2.7 mL blood monovettes
(Sarstedt, Germany), previously rinsed with high-purity air for 4–
6 hours at 50 C to remove contaminants emitted by the monovettes material (plastic). Prior to the sampling procedure a small
amount of heparin (Ebewe Pharma, Austria) was added to the
rinsed monovettes to prevent clotting. In parallel with each blood
sampling, one blank sample containing 2.7 mL of distilled water
was collected using the same protocol and the same materials as
in the case of blood sampling. This was done to identify possible
contaminants stemming from sources other than blood. Blank
samples were analyzed in the same way as blood samples and the
resulting concentration levels were subtracted from the respective values in the associated blood samples.
End-exhaled breath samples were collected into 3 liter Tedlar
bags (SKC Inc., USA) in a CO2 controlled manner using an inhouse made breath sampler developed at Innsbruck Medical
University, Austria.43 In brief, the device selectively extracts the
last segments of each exhalation (i.e., the portion of exhaled
breath characterized by carbon dioxide content higher than a
predened chosen threshold of 3%) and automatically directs
them from a mouthpiece into the sampling bag via a heated
Teon transfer line. Additionally, a separate room air sample
was taken for determining the background levels of all VOCs
detected. Before their use, all bags were thoroughly cleaned to
remove potential pollutants. This was achieved by ushing the
bags ve times with high-purity nitrogen (6.0–99.9999%), followed by overnight heating at 55 C (while lled with N2), reushing and evacuation.
2.3
Blood sample preparation and HS-SPME procedure
Blood VOC analyses followed a slightly modied version of the
extraction procedure developed by Miekisch et al.31,32 Extraction
of volatiles from blood samples was performed in 20 mL headspace vials (Gerstel, Germany) crimped with 1.3 mm butyl/PTFE
septa (Macherey-Nagel, Germany) and containing stirring bars.
Vials were evacuated by means of a membrane pump and 0.3 mL
2136 | Analyst, 2013, 138, 2134–2145
Paper
of Dulbecco's PBS (PAA Laboratories, Austria) was added with
the help of a glass syringe. Heparinized blood samples were
immediately transferred from the monovette into the evacuated
vial using an appropriate needle adapter (Sarstedt, Germany). In
order to prevent losses of poorly soluble species and contamination an effort was made to transfer blood samples avoiding
any contact with laboratory air. Finally, pressure in the vials was
balanced with high-purity nitrogen (6.0–99.9999%).
Head space solid phase microextraction (HS-SPME) was
performed automatically using a multipurpose sampler MPS2
XL (Gerstel, Germany). For extraction purposes the blood
sample vials were incubated in a temperature-controlled
agitator at 37 C and stirred intensively (1200 rpm). Extraction
was achieved by inserting a 75 mm Carboxen-PDMS SPME ber
(Supelco, Canada) into the vials and exposing it to the headspace gas for 50 minutes. This extraction period was found to be
a reasonable trade-off between good detection limits and
sampling duration. In particular, the latter had to be sufficiently
short to avoid unfavorable effects related to blood ageing.
Subsequently, the ber was introduced into the inlet of the gas
chromatograph where the compounds of interest were thermally desorbed at 290 C in splitless mode (1 min). The ber
was conditioned at 290 C for 5 minutes prior to each analysis.
2.4
NTD extraction procedure
Three-bed 23-gauge stainless steel needle trap devices (NTDs)
(PAS Technology, Germany) with side-holes were employed for
the pre-concentration of breath samples. Needle trap devices
are a relatively novel technique for gaseous sample preconcentration and have been described in detail elsewhere in
the literature.44–46 In brief, a certain amount/volume of sample is
drawn through a micro-needle packed with selected sorbent
materials. Due to the small dimensions and low sorbent masses
NTDs offer rapid desorption (additional focusing is not
required) that can be accomplished in the standard inlets of gas
chromatographs. Consequently, contrary to traditional sorbent
trapping, no additional equipment (e.g., thermal desorbers) is
required.
To improve inertness all needles were Silcosteel-treated. The
NTD multilayer sorbent bed consisted of 1 cm of Tenax TA (80/
100 mesh), 1 cm of Carbopack X (60/80 mesh) and 1 cm of
Carboxen 1000 (60/80 mesh). Prior to their use all NTDs were
pre-conditioned at 290 C by ushing them with a high-purity
nitrogen ow (6.0–99.9999%) for 4 h. Since NTDs were found to
exhibit relatively huge differences with respect to extraction
efficiency (deviations of up to 70%, even when originating from
the same production lot) the NTDs used within the study were
pre-selected according to the requirement that their inter-needle variability should be below 10%. This selection was based
on the comparison of NTD-GC-MS analyses of a predened
standard gas mixture containing several breath constituents at
physiological levels using the same conditions as for real breath
samples (i.e. ow 10 mL min 1, 37 C).
NTD trapping of breath constituents was accomplished
dynamically by drawing 200 mL of a breath sample directly from
the Tedlar bag (the latter being heated to 37 C). This was done
This journal is ª The Royal Society of Chemistry 2013
Paper
Analyst
with the help of a membrane pump (Vacuubrand, Germany) at a
steady ow rate of 10 mL min 1, using a mass ow controller
(RED-Y, Burde Co. GmbH, Austria). Consequently, no transfer
line had to be installed between the breath sample and the
needle trap. To minimize the storage time of the breath samples
in the Tedlar bags the NTD extraction was performed shortly
(approximately 5 min) aer breath sampling. Following extraction the NTD was manually introduced into the inlet of the gas
chromatograph where the compounds of interest were thermally desorbed at 290 C in a splitless mode (1 min).
measurements and from 2–13% for breath analyses, which is
satisfactory for the aims of this study. The system response was
found to be linear within the investigated concentration ranges
(see Table 1), with coefficients of variation ranging from 0.907 to
0.999. Blood acetone was not calibrated as the blood analysis
focused on VOCs exhibiting much lower concentrations. As a
matter of fact, acetone signals obtained within this study
generally exceeded the dynamic range of the MS detector.
An exemplary chromatogram from a blood HS-SPME-GCMS
analysis is presented in Fig. 1.
2.5
3.2
Chromatographic analysis
Chromatographic analyses were performed using an Agilent
7890A/5975C GC-MS system (Agilent, USA). During SPME/NTD
desorption, the split/splitless inlet operated in the splitless mode
(1 min), followed by a split mode at ratio 1 : 20. The volatiles of
interest were separated using a PoraBond Q column (25 m 0.32
mm, lm thickness 5 mm, styrene-divinylbenzene copolymer
phase, Varian, USA) working in a constant ow mode (helium at
1.5 mL min 1). The column temperature program involved an
initial increase from 40 C to 260 C at a rate of 7 C min 1 followed by a constant temperature of 260 C for 5 min. The mass
spectrometer worked in a SCAN mode with an associated m/z
range set from 20 to 200 and an acquisition rate of 4.3 scans per s.
The applied GC conditions provided more than 20 scans per
peak. The quadrupole, ion source, and transfer line temperatures
were kept at 150 C, 230 C and 280 C, respectively.
The identication of compounds was performed in two
steps. Firstly, the peak spectrum was checked against the NIST
mass spectral library. Next, the NIST identication was
conrmed by comparing the respective retention times with
retention times obtained on the basis of standard mixtures
prepared from pure compounds (see Table 1). Peak integration
was based on extracted ion chromatograms. The substancespecic m/z ratios selected for this purpose allowed in
numerous cases for a proper separation of compounds from
their neighboring peaks, even when the latter were overlapping
in the total ion count chromatogram. The applied quantier
ions are presented in Table 1.
3
Results and discussion
3.1
Method validation
Limits of detection (LODs) were calculated using extracted ion
chromatograms and the standard deviation of 10 consecutive
blank signals.47 In the case of blood species conditioned human
plasma samples were used as blanks, whereas for breath
compounds humidied zero air containing 100 ppb of isoprene
and 800 ppb of acetone was used for this purpose. The LOD
values ranged from 0.01 to 270 nmol L 1 for blood and from
0.01 to 0.7 ppb for breath. The limit of quantication (LOQ) was
dened as 3 LOD. Relative standard deviations (RSDs) were
calculated on the basis of consecutive analyses of ve independent standard mixtures (in the case of breath) or plasma
samples spiked with calibration solutions (in the case of blood).
The calculated RSDs varied from 1.5–14% for blood
This journal is ª The Royal Society of Chemistry 2013
Volatile blood constituents
Within the present study a total number of 90 volatile organic
compounds were detected in the measured blood samples. The
majority of these (62 species) could reliably be identied and
quantied using the aforementioned procedures. The associated detection and quantication incidences as well as the
observed concentration ranges are given in Table 2. The
remaining compounds could not be identied and/or quantied
properly, either due to the unavailability of pure substances
from commercial vendors, or due to problems related to the
preparation of reliable standard mixtures. The predominant
chemical classes in blood were hydrocarbons and ketones with
nineteen and nine species, respectively. Apart from these, there
were seven heterocyclic compounds, six volatile sulphur
compounds (VSCs), seven aromatics, seven terpenes and three
esters. Only two aldehydes were detected (propanal and 2-propenal), however, it has been reported that the analysis of species
from this chemical class requires special sample treatment (e.g.,
derivatisation).37,38 The observed concentrations ranged from
0.01 nmol L 1 for furan to 6700 nmol L 1 for 2-propenal. More
than half of all quantied species (51%) exhibited mean
concentration values below 1 nmol L 1. The highest mean
levels were noted for 2-propenal (2440 nmol L 1), acetonitrile
(746 nmol L 1) and 3-buten-2-one (156 nmol L 1), however, the
detection rate of the latter was very low (4 out of 28 cases). Ten
compounds (acetone, dimethyl sulphide, methyl acetate,
isoprene, 2-butanone, 2-pentanone, 4-heptanone, 2-heptanone,
p-cymene, and limonene) were found in all samples and another
six exhibited incidence rates higher than 80% (dimethyl selenide, 3-methyl furan, n-hexane, methyl propyl sulphide, noctane, and p-xylene). A relatively high fraction of all volatiles
detected (40%) displayed blood incidence rates below 20%.
3.3
Volatile breath constituents
67 compounds were identied and quantied in breath as well
as in room air samples (see Table 2). This number does not
include species found to be emitted by the employed materials
(e.g., Tedlar bags, septa, NTDs), as it was assumed that the breath
levels of these compounds would be too distorted for a sound
quantitative analysis (e.g., COS, CS2, acetaldehyde, pyrimidine,
cyclohexane, acetophenone). Additionally, room air contaminants appearing in potentially high and variable levels during
sampling such as 1-propanol, 2-propanol and ethanol were
excluded. The highest levels were observed for acetone and
isoprene (mean 950 and 130 ppb respectively) which is
Analyst, 2013, 138, 2134–2145 | 2137
Analyst
Paper
Table 1 Retention times Rt [min], quantifier ions, LODs [nmol L 1, ppb], RSDs (%), coefficients of variation (R2) and linear ranges [nmol L
study for blood and breath measurements. Compounds are ordered with respect to increasing retention time
Blood
1
, ppb] of compounds under
Breath/room air
VOC
CAS
Rt [min]
Quantier
ion
LOD
[nmol L 1]
RSD
[%]
R2
Linear range
[nmol L 1]
LOD
[ppb]
RSD
[%]
R2
Linear range
[ppb]
Propene
Propane, 2-methyl1-Propene, 2-methyl1,3-Butadiene
Acetonitrile
n-Butane
2-Propenal
Furan
Propanal
Acetone
Dimethyl sulde (DMS)
Methyl acetate
Ether, ethyl vinyl
Butane, 2-methyl1-Butene, 2-methylIsoprene
2-Pentene, (E)2-Pentene, (Z)n-Pentane
Dimethyl selenide
1,3-Pentadiene, (E)1,3-Pentadiene, (Z)2-Propenal, 2-methyl3-Buten-2-one
Furan, 2-methyl2,3-Butanedione
2-Butanone
Furan, 3-methylSulde, ethyl methyl
Ethyl acetate
Methyl propionate
1-Pentene, 4-methylButane, 2,3-dimethylThiophene
Pentane, 2-methyl1-Hexene
Benzene
n-Hexane
2,4-Hexadiene, (E,Z)Pyrrole
Pyrazine
2-Pentanone
Furan, 2,5-dimethylSulde, allylmethyl
Pyrrole, 1-methylSulde, methyl propyl
3-Penten-2-one, (E)Hexane, 2-methylThiophene, 3-methylToluene
3-Hexanone
2-Hexanone
Hexanal
g-Butyrolactone
n-Octane
Ethylbenzene
p-Xylene
Styrene
o-Xylene
4-Heptanone
115-07-1
75-28-5
115-11-7
106-99-0
75-05-8
106-97-8
107-02-8
110-00-9
123-38-6
67-64-1
75-18-3
79-20-9
109-92-2
78-78-4
563-46-2
78-79-5
646-04-8
627-20-3
109-66-0
593-79-3
2004-70-8
1574-41-0
78-85-3
78-94-4
534-22-5
431-03-8
78-93-3
930-27-8
624-89-5
141-78-6
554-12-1
691-37-2
79-29-8
110-02-1
107-83-5
592-41-6
71-43-2
110-54-3
5194-50-3
109-97-7
290-37-9
107-87-9
625-86-5
10152-76-8
96-54-8
3877-15-4
3102-33-8
591-76-4
616-44-4
108-88-3
589-38-8
591-78-6
66-25-1
96-48-0
111-65-9
100-41-4
106-42-3
100-42-5
95-47-6
123-19-3
3.99
8.21
8.43
8.48
9.04
9.08
10.29
10.65
10.83
10.98
11.52
12.35
12.75
13.02
13.10
13.22
13.44
13.53
13.65
13.90
13.92
14.02
14.20
14.87
15.25
15.34
15.39
15.51
15.87
16.16
16.44
16.49
16.90
16.98
17.00
17.26
17.42
17.69
18.03
18.15
18.46
19.09
19.13
19.13
19.40
19.74
20.07
20.61
21.05
21.32
22.42
22.62
22.84
23.16
24.51
24.52
24.73
24.98
25.11
25.38
41
43
56
54
41
43
56
68
58
58
62
43
72
57
55
67
55
55
43
95
67
67
70
55
82
43
72
82
61
43
57
56
43
84
43
56
78
57
82
67
80
43
96
88
81
61
69
85
97
91
57
43
56
42
85
91
91
104
91
71
3.7
0.23
0.11
0.07
14.8
0.13
270
0.012
1.3
—
0.1
1
0.04
0.07
0.05
0.04
0.04
0.04
0.1
0.03
0.03
0.02
0.9
40
0.01
4
0.4
0.015
0.06
0.1
0.13
0.03
0.06
0.01
0.08
0.02
0.015
0.02
0.02
0.015
4.5
0.25
0.025
0.03
0.1
0.04
2.5
0.02
0.02
0.03
0.15
0.15
—
—
0.04
0.4
0.07
0.1
0.08
0.05
10
4.5
4.5
5
13
3.5
6
3
4
—
1.5
9
7
5
4
4
3
6
3
4
7
10
7.5
10
4
10
5.5
4.5
5
13
12
5
5.5
3
4
3
2
2.5
7
13
9
8
6
3
12
2.5
4
7
4.5
6.5
8.5
7
—
—
7
6
4.5
9
5
9
0.907
0.999
0.989
0.999
0.998
0.999
0.998
0.999
0.997
—
0.991
0.993
0.999
0.999
0.996
0.995
0.999
0.998
0.999
0.997
0.999
0.999
0.999
0.986
0.999
0.989
0.994
0.999
0.997
0.998
0.981
0.996
0.997
0.999
0.999
0.999
0.999
0.999
0.999
0.995
0.999
0.999
0.999
0.994
0.999
0.991
0.991
0.999
0.998
0.999
0.996
0.999
—
—
0.998
0.999
0.999
0.980
0.999
0.998
11–53
0.8–13
0.3–26
0.2–26
44–2800
0.4–26
800–9000
0.03–10
4–66
—
0.3–100
3–93
0.12–6
0.2–15
0.15–9
0.1–53
0.12–6
0.1–2.6
0.3–17.5
0.08–12
0.09–7.6
0.06–3.6
2.6–318
120–3600
0.03–6
13–154
1.2–250
0.05–6
0.16–8
0.3–11
0.4–30
0.07–8.4
0.18–7.3
0.03–7
0.25–9
0.06–8
0.04–10
0.07–5
0.06–2.7
0.04–14
13–144
0.8–208
0.07–12
0.09–80
0.03–166
0.12–134
7.5–122
0.05–8
0.03–11
0.1–11
0.5–32
0.4–60
—
—
0.12–6.5
1–9
0.2–10
0.3–10
0.25–10
0.12–12
0.7
0.12
0.05
0.06
0.24
0.12
0.13
0.01
0.17
0.1
0.05
0.2
0.05
0.05
0.03
0.01
0.02
0.02
0.04
0.01
0.01
0.01
0.03
0.15
0.01
0.2
0.08
0.01
0.02
0.05
0.06
0.02
0.02
0.01
0.04
0.01
0.03
0.01
0.01
0.03
—
0.02
0.02
0.01
0.05
0.01
0.02
0.01
0.01
0.1
0.04
0.06
0.2
0.2
0.01
0.07
0.7
0.1
0.3
0.01
10
9
7
3
3.5
8
4
7
7
6
6.6
9
7
6
10
5.5
4
3.5
8
10
4.5
3.5
8
7
7
13
7.5
8.5
5.5
6
6.5
8
8.5
4
11
7
7
8
6
8
—
3
9
5.5
11
6
6
8
8
8
7
7
9
2
10
4
7
11
8.2
2.5
0.999
0.995
0.997
0.999
0.990
0.982
0.999
0.985
0.998
0.995
0.998
0.999
0.998
0.994
0.998
0.995
0.999
0.999
0.995
0.997
0.998
0.997
0.992
0.993
0.995
0.987
0.999
0.994
0.999
0.996
0.992
0.994
0.999
0.999
0.995
0.995
0.994
0.994
0.991
0.993
—
0.999
0.978
0.994
0.980
0.996
0.997
0.996
0.995
0.998
0.996
0.995
0.993
0.999
0.995
0.999
0.999
0.997
0.996
0.998
2–60
0.4–19
0.15–20
0.2–10
0.7–30
0.3–19
0.4–31
0.03–9
0.5–32
0.3–1500
0.15–25
0.5–20
0.15–10.5
0.14–12
0.08–6.5
0.04–270
0.06–3.4
0.06–2
0.12–18
0.05–6
0.03–7
0.03–3.6
0.09–12
0.45–15
0.03–11
0.6–54
0.25–25
0.03–6
0.05–5
0.14–10
0.2–8
0.07–6.5
0.06–6.5
0.03–5
0.12–7
0.03–7
0.1–10.5
0.03–6
0.04–2
0.08–6.6
—
0.05–4.5
0.05–9
0.03–10
0.15–10.5
0.03–10
0.06–7.5
0.02–6
0.02–5.2
0.3–9
0.12–4
0.2–5
0.6–15
0.5–20
0.03–6
0.2–7.5
2–8
0.3–9
1–9
0.02–7.5
2138 | Analyst, 2013, 138, 2134–2145
This journal is ª The Royal Society of Chemistry 2013
Paper
Table 1
Analyst
(Contd. )
Blood
Breath/room air
VOC
CAS
Rt [min]
Quantier
ion
LOD
[nmol L 1]
RSD
[%]
R2
Linear range
[nmol L 1]
LOD
[ppb]
RSD
[%]
R2
Linear range
[ppb]
2-Heptanone
Benzaldehyde
Octane, 4-methyla-Methylstyrene
a-Pinene
b-Pinene
3-Carene
p-Cymene
Limonene
n-Decane
g-Terpinene
Eucalyptol
n-Undecane
Menthone
110-43-0
100-52-7
2216-34-4
98-83-9
80-56-8
127-91-3
13466-78-9
99-87-6
138-86-3
124-18-5
99-85-4
470-82-6
1120-21-4
10458-14-7
25.78
26.01
26.67
27.52
27.69
28.68
29.06
29.60
29.80
30.08
30.08
30.35
32.64
33.49
43
106
43
118
93
93
93
119
68
57
93
43
57
112
0.2
2.5
0.15
0.1
0.06
0.04
0.9
0.1
0.08
0.3
1
0.8
0.7
0.6
10
12
8
9
7
7
8
9.5
7
5
12
13
8
14
0.999
0.978
0.999
0.999
0.982
0.993
0.991
0.986
0.991
0.984
0.992
0.996
0.924
0.980
0.6–12
8–145
0.45–6.6
0.3–10
0.2–12
0.1–10
3–12
0.3–36
0.24–69
0.9–12
3–51
2.3–65
2–11
1.7–62
0.03
0.3
0.04
0.01
0.02
0.01
0.02
0.01
0.01
0.03
0.02
0.1
0.03
0.06
2.5
12.5
10
13
7.5
10
13
5.5
5
6
9
10
9
12
0.998
0.998
0.997
0.997
0.981
0.981
0.988
0.997
0.991
0.996
0.990
0.991
0.990
0.977
0.08–6.5
0.9–9
0.1–5.5
0.03–8
0.06–5.8
0.03–6
0.06–8
0.03–6.5
0.03–5
0.8–5.5
0.06–10
0.25–11
0.1–4
0.18–10
Fig. 1
An exemplary chromatogram from a blood HS-SPME-GCMS analysis.
consistent with literature data.22,48 The majority of compounds
(65%) exhibited sub-ppb levels (considering means). The mean
concentration values of the remaining volatiles spread around 1–
10 ppb. Hydrocarbons comprised 34% of all quantied species,
ketones 10%, aromatics 10%, volatile sulphur compounds 9%,
terpenes 12%, heterocyclic compounds 7%, esters 3%, and
aldehydes 6%. The remaining classes (e.g., nitriles, ethers,
selenides) were represented only by single species. Twenty
compounds exhibited incidence rates of 100% and another 5
were present in all samples but one (see Table 2). Around 16% of
all quantied analytes exhibited occurrence rates below 20%.
3.4 Comparison of blood, breath and room air levels of
quantied VOCs
Although the blood levels of VOCs obtained within this study
refer to peripheral venous blood, comparing these values with
This journal is ª The Royal Society of Chemistry 2013
breath and room air concentrations can provide valuable
information regarding the origin (endogenous/exogenous) of
some volatile species. For instance, high occurrence in blood
and breath and low room air levels may point towards blood as a
main source of an analyte in breath. Conversely, high room air
concentrations and low levels in exhaled breath and blood are
typical for exogenous contaminants. Several compounds were
found to occur exclusively, or at higher concentrations in the
breath and blood of smokers. However, due to the fact that only
six smokers were recruited within this study the classication of
these species was additionally conrmed by the qualitative
ndings from our previous study.49
For 32 compounds signicant differences between breath
and room air levels were found (Wilcoxon signed-rank test).
Twenty-two of them exhibited higher levels in breath than in
room air samples (see Table 2). Among these species 16
showed detection frequencies higher than 80%. The highest
Analyst, 2013, 138, 2134–2145 | 2139
Detection (nd) and quantification (nq) incidences of the compounds under study, together with breath, blood, and room air concentration ranges. n.s. – not significant
Blood
Breath
Analyst
2140 | Analyst, 2013, 138, 2134–2145
Table 2
Room air
Range (mean)
[nmol L 1]
Incidence
nd(nq)
Range
(mean) [ppb]
Incidence
nd(nq)
Range
(mean) [ppb]
p value Wilcoxon
test breath vs.
room air
Propene
Propane, 2-methyl1-Propene, 2-methyl1,3-Butadiene
Acetonitrile
n-Butane
2-Propenal
Furan
Propanala
Acetone
Dimethyl sulde
Methyl acetate
Ether, ethyl vinyl
Butane, 2-methyl1-Butene, 2-methylIsoprene
2-Pentene, (E)2-Pentene, (Z)n-Pentane
Dimethyl selenide
1,3-Pentadiene, (E)1,3-Pentadiene, (Z)2-Propenal, 2-methyl3-Buten-2-one
Furan, 2-methyl2,3-Butanedione
2-Butanone
Furan, 3-methylSulde, ethyl methyl
Ethyl acetate
Methyl propionate
1-Pentene, 4-methylButane, 2,3-dimethylThiophene
Pentane, 2-methyl1-Hexene
Benzene
n-Hexane
2,4-Hexadiene, (E,Z)Pyrrole
Pyrazine
2-Pentanone
Furan, 2,5-dimethyl-
12(12)
5(2)
1(1)
8(8)
20(20)
5(5)
13(13)
14(14)
15(15)
28(28)
28(28)
28(27)
6(5)
6(5)
0(0)
28(28)
1(1)
0(0)
19(18)
25(25)
2(2)
2(0)
0(0)
4(4)
2(2)
0(0)
28(28)
23(10)
12(5)
2(2)
13(13)
0(0)
0(0)
16(16)
4(3)
10(10)
15(15)
24(24)
0(0)
17(17)
15(9)
28(28)
6(6)
4–61.5 (14)
0.8–1.5 (1.2)
3.4
0.05–0.27 (0.17)
101–2334 (745)
0.13–0.46 (0.34)
880–6700 (2440)
0.01–0.36 (0.1)
11–29 (16)
—
2–32.8 (8.3)
3.4–156 (30.5)
0.08–0.23 (0.13)
0.14–2.1 (0.74)
—
3.5–34 (14.6)
0.13
—
0.19–0.81 (0.37)
0.13–0.5 (0.26)
0.09–0.1 (0.09)
—
—
126–181 (156)
0.05–0.26 (0.15)
—
8.4–72 (35)
0.03–0.1 (0.06)
0.2–0.82 (0.39)
0.5–5 (2.7)
0.3–15 (2.8)
—
—
0.03–0.14 (0.05)
0.26–0.53 (0.35)
0.03–0.21 (0.08)
0.03–0.98 (0.26)
0.02–0.57 (0.17)
—
0.25–1.89 (1.04)
15–32 (20)
9.4–105.4 (34.7)
0.2–0.66 (0.41)
0(0)
25(20)
28(28)
10(7)
26(26)
13(13)
28(28)
21(21)
28(28)
28(28)
28(28)
27(26)
16(12)
28(28)
4(4)
28(28)
6(4)
6(6)
28(28)
26(26)
3(3)
3(2)
28(28)
28(28)
28(28)
28(28)
26(26)
23(23)
13(2)
21(16)
0(0)
15(5)
12(8)
2(2)
28(27)
12(11)
28(28)
28(28)
4(4)
17(17)
0(0)
28(28)
5(5)
—
0.4–4.7 (1.4)
0.6–2.8 (1.3)
0.2–1.6 (0.8)
13–78.5 (31.5)
0.75–7.6 (2.4)
2.9–19 (5.9)
0.08–2.3 (0.42)
5–66 (18.3)
281–2525 (950)
1.4–28 (5)
0.64–18.8 (2.6)
0.15–0.67 (0.34)
0.6–9.5 (2.3)
0.08–0.35 (0.15)
31–273 (131)
0.1–0.22 (0.16)
0.08–1.34 (0.56)
0.34–22 (1.8)
0.16–0.64 (0.35)
0.2–0.66 (0.44)
0.1–0.2 (0.15)
0.4–2.9 (1.2)
0.8–14.4 (3.8)
0.1–3.7 (0.55)
1.4–187 (29)
0.5–5 (2.2)
0.05–0.39 (0.18)
0.05–0.06 (0.06)
0.16–9.4 (1.2)
—
0.08–0.1 (0.09)
0.07–1 (0.24)
0.05–0.08 (0.06)
0.1–6.4 (0.54)
0.05–0.44 (0.16)
0.16–5.8 (0.8)
0.07–1.8 (0.32)
0.25–0.94 (0.62)
0.09–0.27 (0.17)
—
0.1–2.1 (0.62)
0.62–2.78 (1.6)
0(0)
21(18)
28(27)
10(5)
26(26)
13(13)
21(21)
21(21)
28(28)
28(28)
28(16)
26(17)
14(7)
28(28)
4(3)
28(28)
6(3)
6(5)
28(28)
6(4)
3(0)
2(1)
28(28)
28(28)
28(28)
28(28)
26(26)
23(23)
0(0)
22(22)
0(0)
5(1)
11(10)
2(1)
28(26)
11(10)
28(28)
28(28)
3(0)
17(16)
0(0)
28(21)
3(1)
—
0.4–13 (1.6)
0.6–3.9 (1.3)
0.2–0.34 (0.27)
10–117 (43.6)
0.8–2.5 (1.5)
2–21.5 (7.7)
0.07–0.77 (0.22)
3.7–432 (77.6)
9–454 (134)
0.13–1.3 (0.38)
0.55–2.6 (1.1)
0.15–2.1 (0.8)
0.64–13.5 (2.8)
0.1–0.21 (0.17)
0.9–18 (5)
0.07–0.1 (0.086)
0.06–0.17 (0.12)
0.24–35 (2.4)
0.08–0.14 (0.1)
—
0.06
0.3–3.5 (1.2)
0.7–11.3 (2.4)
0.1–3.0 (0.4)
0.9–7 (3)
0.35–27 (6.2)
0.03–0.24 (0.08)
—
0.23–5.1 (1.3)
—
0.12
0.06–0.3 (0.14)
0.03
0.14–1 (0.34)
0.04–0.2 (0.12)
0.2–0.75 (0.4)
0.07–2.84 (0.37)
—
0.08–0.26 (0.15)
—
0.06–0.34 (0.09)
0.07
—
n.s.
n.s.
n.s.
1.53
n.s.
n.s.
n.s.
5.85
3.79
3.79
1.32
n.s.
1.04
—
3.79
—
3.13
n.s.
8.30
—
—
n.s.
3.31
n.s.
1.86
3.77
1.27
—
7.79
—
—
n.s.
—
n.s.
n.s.
n.s.
n.s.
—
n.s.
—
3.79
n.s.
Tentative origin
Smoking
Exogenous
10
2
10
10
10
10
4
10
3
Exogenous
10
6
10
2
Blood-borne
Smoking
Smoking
10
6
Blood-borne
Smoking
Smoking
10
3
Blood-borne
Smoking
10
10
10
5
10
4
6
6
4
4
4
Smoking
Exogenous
Blood-borne
Blood-borne
Blood-borne
Exogenous
Blood-borne
Exogenous
Smoking
10
6
Blood-borne
Smoking
Paper
This journal is ª The Royal Society of Chemistry 2013
VOC
Incidence
nd(nq)
(Contd. )
Blood
Breath
Paper
This journal is ª The Royal Society of Chemistry 2013
Table 2
Room air
VOC
Incidence
nd(nq)
Range (mean)
[nmol L 1]
Incidence
nd(nq)
Range
(mean) [ppb]
Incidence
nd(nq)
Range
(mean) [ppb]
p value Wilcoxon
test breath vs.
room air
Sulde, allylmethyl
Pyrrole, 1-methylSulde, methyl propyl
3-Penten-2-one, (E)Hexane, 2-methylThiophene, 3-methylToluene
3-Hexanone
2-Hexanone
Hexanal
g-Butyrolactone
n-Octane
Ethylbenzene
p-Xylene
Styrene
o-Xylene
4-Heptanone
2-Heptanone
Benzaldehyde
Octane, 4-methyla-Methylstyrene
a-Pinene
b-Pinene
3-Carene
p-Cymene
Limonene
n-Decane
g-Terpinene
Eucaliptol
n-Undecane
Menthone
20(20)
5(4)
25(25)
5(5)
9(9)
11(1)
22(22)
6(1)
7(7)
0(0)
0(0)
25(25)
4(1)
23(23)
10(10)
3(3)
28(27)
28(28)
0(0)
7(7)
3(2)
0(0)
4(4)
4(4)
28(27)
28(28)
24(22)
9(9)
10(7)
3(3)
3(3)
0.18–21.7 (2.7)
0.41–0.6 (0.48)
0.18–76.4 (4.4)
6.3–20.3 (10)
0.03–0.57 (0.13)
0.04
0.08–3.1 (0.6)
0.48
0.1–0.5 (0.36)
—
—
0.1–3.45 (1.3)
1.96
0.08–11.2 (0.96)
0.13–0.73 (0.36)
0.38–5.2 (2.2)
0.2–2.15 (0.83)
0.6–5.7 (2.7)
—
0.44–2.4 (0.97)
0.19–0.20 (0.2)
—
0.43–1.5 (1.08)
2–4.4 (3.4)
0.3–5.4 (1.1)
0.94–42.6 (9.3)
0.62–13.2 (3.1)
0.06–1.7 (0.41)
3.9–10 (6.41)
1.9–2.6 (2.2)
2.4–7.8 (4.9)
25(25)
0(0)
27(27)
0(0)
27(27)
20(15)
28(23)
0(0)
0(0)
8(2)
20(20)
23(23)
14(6)
3(1)
27(26)
1(1)
17(9)
17(1)
28(9)
3(1)
13(7)
27(27)
22(22)
9(9)
28(28)
28(28)
25(16)
8(3)
10(9)
14(9)
7(7)
0.09–12.7 (1.6)
—
0.05–39 (2.2)
—
0.04–0.77 (0.15)
0.02–0.08 (0.03)
0.3–8.6 (1.42)
—
—
0.63–0.67 (0.65)
0.63–7.96 (2.8)
0.04–0.22 (0.12)
0.22–1.92 (0.61)
7.3
0.22–4.5 (0.92)
2.68
0.02–0.05 (0.03)
0.1
1–3.4 (1.8)
0.27
0.04–0.24 (0.13)
0.17–3.7 (0.6)
0.14–3 (0.59)
0.1–0.52 (0.26)
0.02–0.6 (0.14)
0.27–7.42 (1.46)
0.07–0.31 (0.14)
0.05–0.14 (0.09)
0.28–2.8 (1.16)
0.08–4.5 (0.6)
0.36–19.7 (6)
16(7)
0(0)
20(12)
0(0)
27(27)
7(4)
28(28)
0(0)
0(0)
8(8)
20(20)
23(23)
20(8)
13(1)
27(27)
1(0)
0(0)
17(0)
27(23)
5(1)
13(4)
27(27)
22(22)
9(6)
28(23)
28(28)
24(19)
5(5)
4(2)
13(11)
6(0)
0.03–0.2 (0.07)
—
0.03–0.13 (0.06)
—
0.05–0.37 (0.15)
0.02–0.035 (0.024)
0.38–2.26 (1.1)
—
—
1.46–3 (2.1)
0.35–8.48 (2.23)
0.05–0.17 (0.09)
0.25–0.6 (0.4)
2.16
0.25–0.73 (0.4)
—
—
—
1–19.8 (2.8)
0.44
0.04–0.06 (0.05)
0.05–0.72 (0.3)
0.04–0.92 (0.22)
0.07–0.13 (0.09)
0.015–0.11 (0.04)
0.07–0.93 (0.35)
0.08–0.6 (0.19)
0.08–1.9 (0.74)
0.39–0.6 (0.49)
0.09–0.53 (0.22)
—
1.23
—
6.28
—
4.36
1.83
n.s.
—
—
7.81
n.s.
3.86
n.s.
—
n.s.
—
3.91
—
2.03
—
n.s.
1.52
4.98
1.17
9.98
7.26
2.14
3.91
3.91
n.s.
1.56
10
5
Blood-borne
10
6
Blood-borne
10
10
2
Exogenous
Exogenous
10
3
Exogenous
10
3
Blood-borne
10
3
Blood-borne
10
3
Exogenous
10
10
10
10
10
10
10
10
2
Blood-borne
Blood-borne
Blood-borne
Blood-borne
Blood-borne
Exogenous
Blood-borne
Blood-borne
10
2
4
3
2
6
6
4
3
3
Blood-borne
In 20% of cases the separation of propanal from acetone was not satisfactory (resolution 60–70%).
Analyst
Analyst, 2013, 138, 2134–2145 | 2141
a
Tentative origin
Analyst
breath-to-room-air-ratios (considering means) were noted for
methylpropylsulde (37), isoprene (26), allylmethylsulde (21),
dimethylsulde (13) and 2,3-butanedione (10). Apart from six
species (2,3-butanedione, 3-buten-2-one, 4-heptanone, g-terpinene and a-pinene and b-pinene) the blood incidence rates of
these compounds were similar to the ones in breath, suggesting
that a major part of the amount exhaled in breath stems from
blood. In the case of ten analytes (propanal, decane, 2-butanone, benzaldehyde, hexanal, 3-methyl thiophene, 2-methyl
butane, ethylacetate, acetonitrile and 2-methyl hexane) room air
levels were signicantly higher than breath levels. Thus, these
species – despite their presence in blood – are most likely
environmental contaminants. Several compounds (n-hexane, npentane, toluene, 2-methyl pentane, furan) were found to have
comparable levels in breath and room air samples. However,
the high blood detection rate of these species implies that at
least part of their blood abundance stems from exogenous
sources and that the similarity between breath and room air
levels probably results from an equilibration between blood and
room atmosphere.
Five ketones were detected in all blood samples: acetone, 2butanone, 2-pentanone, 2-heptanone and 4-heptanone. This
nding is not surprising as these analytes are also omnipresent
in human urine.15,50 Acetone, 2-butanone and 2-pentanone were
also omnipresent in breath, however, only acetone and 2-pentanone exhibited higher concentrations in breath than in room
air. The abundances of 2-butanone were higher in room air than
in breath suggesting a considerable contribution of room air to
2-butanone blood levels. Both 2-butanone and 2-pentanone
showed comparable blood levels ranging from 10–105 nmol
L 1. However, in breath 2-pentanone was found at four-fold
lower concentrations than 2-butanone. This difference could be
explained by a higher blood solubility of 2-pentanone in blood
as well as increased room air levels of 2-butanone. Although 2heptanone and 4-heptanone were present in all blood samples
their occurrence in breath was markedly lower (60% of all
volunteers). This is most probably due to low (close-to-LOD)
breath concentrations of heptanone isomers. Interestingly, in
blood 2-heptanone showed slightly higher concentrations than
4-heptanone, whereas in urine the levels of 4-heptanone were
reported to signicantly exceed those of 2-heptanone.51 Perhaps
the renal removal of 4-heptanone from the blood stream is more
effective than for its isomer. 2,3-Butanedione was ubiquitous in
breath showing on average three times higher levels in exhaled
air than in room air. However, the fact that it was never detected
in blood suggests an exogenous source of this compound. Since
2,3-butanedione is a common constituent of butter it is
conceivable that the oral cavity might act as a reservoir for this
volatile. The remaining ketones (3-buten-2-one, 3-penten-2-one,
2-hexanone, and 3-hexanone) generally showed much lower
detection rates (15–25%) in blood and were never detected in
breath samples (with the exception of 3-buten-2-one).
Dimethyl sulphide (DMS) was the only omnipresent volatile
sulphur compound and also exhibited the highest abundances
in blood and breath samples (mean concentrations of 8.3 nmol
L 1 and 5 ppb, respectively). The blood DMS values obtained
within this study were higher than the ones observed by
2142 | Analyst, 2013, 138, 2134–2145
Paper
Miekisch et al.31 in mechanically ventilated patients. While it is
difficult to compare such different groups of individuals, this
discrepancy could be explained, e.g., by different diet regimes.
Detection frequencies of methylpropylsulde (MPS) and allylmethylsulde (AMS) were slightly lower (89% and 71% in blood
and 96% and 90% in breath, respectively), however, the
observed concentration ranges in blood were comparable with
DMS (mean concentrations of 4.4 nmol L 1 and 2.7 nmol L 1,
respectively). Interestingly, room air levels of DMS, AMS and
MPS were a factor of 11–21 lower than in breath, thereby
rendering these species potentially blood-borne compounds.
The levels of the remaining VSCs were below 0.5 nmol L 1 in
blood and 0.06 ppb in breath.
A total of 24 hydrocarbons (HCs) were detected in blood and/
or breath samples, making this family the predominant chemical class within this study. Isoprene showed an incidence of
100% in both uids and also was present at the highest
concentrations (3.5–34 nmol L 1 in blood and 31–273 ppb in
breath).52 Apart from isoprene only four HCs (n-pentane, nhexane, n-octane, and n-decane) were found in more than 50%
of all blood samples. These four HCs also showed high detection
frequencies in breath samples. Furthermore, for n-octane and ndecane signicant differences between breath and room air
levels were noted. Breath levels of n-octane were found to be
higher than in room air, while for n-decane the opposite was
true. Also, n-pentane and n-hexane exhibited similar levels in
breath and room air. This points towards room air as a major
source for the appearance of these HCs in blood. Several
hydrocarbons (e.g., isobutane, 2-methyl-1-propene, 2-methyl
butane 2-methyl pentane, and 2-methyl hexane) were omnipresent in breath and room air and simultaneously relatively
rare in blood. Within this group 2-methyl butane and 2-methyl
hexane showed higher concentrations in room atmosphere than
in breath. For the remaining ones no statistically signicant
difference between expired air and room air could be observed.
The low blood detection incidence of these HCs might be
explained by the low blood solubility of these species,53 implying
that the venous blood concentrations were probably close to the
analytical limits of the applied method. Very low, close-to-LOD
breath levels can also explain the low blood occurrence of some
other HCs (e.g., 4-methyl-1-pentene, 2,3-dimethyl butane).
Several unsaturated hydrocarbons were present exclusively (1,3pentadiene, 2,4-hexadiene), or predominantly (1,3-butadiene, 2pentene) in the breath of smokers, this being consistent with
previous studies.49 The detection frequency of the remaining
HCs was usually below 30%.
Seven aromatic compounds were quantied in blood and
breath samples. The highest incidences were noted for benzene,
toluene, and styrene. Benzene, toluene, and o-xylene were found
to be smoking-related species. For example, benzene exhibited
ten-fold higher levels in the blood and breath of smokers (0.14–
0.98 (0.56) nmol L 1 and 0.57–5.7 (2.7) ppb, respectively) than in
non-smokers (0.03–0.1 (0.06) nmol L 1 and 0.16–0.6 (0.27) ppb,
respectively). Similar differences between smokers and nonsmokers were also observed for toluene (0.36–3.1 (1.6) nmol L 1
vs. 0.08–0.48 (0.22) nmol L 1 for blood, and 0.7–8.6 (3.7) ppb vs.
0.3–1.3 (0.6) ppb for breath).
This journal is ª The Royal Society of Chemistry 2013
Paper
Analyst
Concentration levels of heterocyclic compounds were relatively low, typically falling below 0.5 nmol L 1 in blood and 0.5
ppb in breath. Only pyrazine showed higher blood concentrations ranging from 15–32 nmol L 1. Furan, 2-methyl furan and
2,5-dimethyl furan exhibited higher abundances in exhaled air
and the blood of smokers. Interestingly, 3-methyl furan was
found to be present in more than 80% of breath and blood
samples, and its levels in breath were signicantly higher than
those in room air. These ndings point towards blood as a main
origin of this analyte. One possible source of this volatile in
human organisms could be the degradation of isoprene
induced by alkoxy radicals.54 Two pyrroles were found in blood
samples, namely pyrrole and 1-methyl pyrrole. Their incidences
were relatively low, particularly when compared to their high
occurrence in urine samples.15 However, it must be remembered in this context that due to the pre-concentration capabilities of kidneys VOC levels in urine are usually much higher
than those in blood and thus much easier to detect. Pyrrole was
found both in breath and blood samples with similar occurrence rates, however, breath concentrations were comparable to
room air levels.
A number of terpenes were detected in this study. However,
only two species (p-cymene and limonene) were present in all
matrices. They also showed higher levels in breath than in room
air (breath-to-room-air-ratios of 3.8 and 4.2, respectively,
considering means). All remaining terpenes also exhibited
higher concentrations in exhaled air than in room air. a-Pinene
and b-pinene were found in 96% and 78% of all breath samples,
respectively, but their blood incidence was very low. Other
terpenes generally occurred in less than 35% of all samples.
Only two aldehydes (2-propenal and propanal) were found in
blood samples showing incidence rates of 50%. The levels of
2-propenal were particularly high and ranged from 880 to 6700
Table 3
(2440) nmol L 1. This compound was omnipresent in breath
and room air, however, the difference between these matrices
was not signicant. Propanal exhibited lower blood levels (11–
29 nmol L 1) and its mean breath level was four times lower
than the corresponding room air concentration, thus indicating
an exogenous origin of this species in blood and breath. A
similar conclusion can be drawn for hexanal. The remaining
aldehydes were found exclusively in breath and room air
samples and not in blood.
Three esters were quantied within this study. Methyl
acetate was omnipresent in blood and breath samples and
exhibited higher levels in breath than in room atmosphere, this
being consistent with the literature.39 Methylpropionate was
detected in 46% of blood samples, however, it was not found in
breath. It seems that this poor detection incidence may be due
to much lower blood levels of this compound compared to
methyl acetate. Dimethyl selenide was ubiquitous in all samples
with detection incidences of 90%. Considering its low room air
levels it seems that this volatile is a blood-borne compound.
Apart from 2-propenal only acetonitrile exhibited blood
concentrations at the mmol L 1 level. Although this substance
was also present in the blood and exhaled air of non-smokers,
its levels in smokers were substantially higher (mean 463 nmol
L 1 vs. 1405 nmol L 1 for blood and 25 ppb vs. 52 ppb for
breath). These levels of acetonitrile agree well with the values
obtained by Houeto et al.29 in the blood of smoking individuals
(2200–10 000 nmol L 1, mean 4450 nmol L 1).
A comparison of the blood VOC levels obtained within this
study with selected data from the literature is presented in
Table 3. Although human blood concentration data are relatively sparse and were frequently obtained for a specic group of
individuals (e.g. smokers, mechanically ventilated patients) a
reasonable agreement could be achieved.
Comparison of the blood VOC levels obtained within this study with some literature data
This study
Literature data
VOC
Range (mean) [nmol L 1]
Remarks
Range (mean) [nmol L 1]
1,3-Butadiene
Acetonitrile
DMS
Isoprene
0–0.93 (0.08) (ref. 28)
2200–10 000 (4450) (ref. 29)
0–1.72 (0.41) (ref. 31)
15–70 (37) (ref. 35)
4.5–38 (14) (ref. 34)
0.5–24.4 (9) (ref. 31)
0–58 (11.8) (ref. 31)
(99) (ref. 24)
0–3.9 (0.3) (ref. 28)
0.14–4.6 (0.77) (ref. 30)
0.12–21.2 (4.3) (ref. 26)
0.4–6.2 (1.2) (ref. 28)
0.32–14.1 (1.8) (ref. 30)
(1.67) (ref. 24)
0.41–9.31 (2.26) (ref. 25)
0.25–54.4 (9) (ref. 26)
0.81–27.2 (3.6) (ref. 30)
(5.65) (ref. 24)
0.25–53 (4.8) (ref. 25)
(3.49) (ref. 24)
0.34–50 (2.5) (ref. 25)
Smokers
Smokers
Mechanically ventilated patients
Healthy volunteers
Rebreathing experiment
Mechanically ventilated patients
Mechanically ventilated patients
General U.S. population
Smokers
Smokers
Non-occupational exposure
Smokers
Smokers
General U.S. population
General U.S. population
Non-occupational exposure
Smokers
General U.S. population
General U.S. population
General U.S. population
General U.S. population
0.05–0.27 (0.17)
101–2334 (745)
3.5–34 (14.6)
3.5–34 (14.6)
Pentane
2-Butanone
Furan, 2,5-dimethylBenzene
Toluene
p-Xylene
This journal is ª The Royal Society of Chemistry 2013
0.19–0.81 (0.37)
8.4–72 (35)
0.2–0.66 (0.41)
0.03–0.98 (0.26)
0.08–3.1 (0.6)
0.08–11.2 (0.96)
Analyst, 2013, 138, 2134–2145 | 2143
Analyst
4
Conclusions
The present study was aimed at providing a comprehensive list
of concentration reference values for a wide range of volatile
organic compounds in the blood and breath of healthy volunteers. For this purpose gas chromatography with mass spectrometric detection coupled with two pre-concentration techniques
(SPME and NTD) was applied. 74 species were quantied in the
breath and blood of 28 healthy volunteers. The observed
concentrations ranged over several orders of magnitude, from
10 pmol L 1 to 6.7 mmol L 1 (without acetone) in blood and from
0.02 ppb to 2500 ppb in breath. The quantied compounds
belonged to several chemical classes, however, hydrocarbons
were the most numerous chemical family (24 species). Other
well-represented classes were ketones (10), terpenes (8),
heterocyclic compounds (7) and aromatic compounds (7).
Twelve compounds were simultaneously present in both uids
(>80% occurrence). In the case of 22 species breath levels were
signicantly higher than room air levels (Wilcoxon signed-rank
test). Within this group 11 volatiles (isoprene, acetone, limonene, dimethyl selenide, p-cymene, 2-pentanone, methyl propyl
sulphide, dimethyl sulphide, n-octane, 4-heptanone, and methyl
acetate) also showed very high occurrence in blood, which
seems to render blood a main source for their presence in
breath. Consequently, these species are the most promising
breath-borne markers of human presence. On the other side, ten
species (propanal, decane, 2-butanone, benzaldehyde, hexanal,
3-methyl thiophene, 2-methyl butane, ethylacetate, acetonitrile,
and 2-methyl hexane) exhibited higher levels in room air than in
breath which suggests an exogenous origin of these compounds.
Although a relatively small number of smokers were involved in
this study, several blood and breath compounds were found to
be smoking related. This group included unsaturated hydrocarbons (1,3-butadiene, 1,3-pentadiene, 2-butene, 2,4-hexadiene), furans (furan, 2-methyl furan, 2,5-dimethylfuran), and
acetonitrile. The fact should be stressed that the proposed
classication of quantied species into systemic (blood-borne)
and exogenous volatiles is certainly tentative as some species
may originate from several distinct sources. In particular, the
term “blood-borne” does not necessarily mean that the
substance is of metabolic origin. It also includes diet-related or
drug-related species. The blood and blood-borne breath species
exhibiting incidence higher than 80% can be considered as
potential markers of human presence to be veried during
further eld studies.
Acknowledgements
The research leading to these results has received funding from
the European Community's Seventh Framework Program (FP7/
2007-13) under grant agreement no. 217967 (“SGL for USaR”
project, Second Generation Locator for Urban Search and
Rescue Operations, http://www.sgl-eu.org). We appreciate
funding from the Austrian Federal Ministry for Transport,
Innovation and Technology (BMVIT/BMWA, project 836308,
KIRAS). P.M, J.K., and K.U. gratefully acknowledge support from
the Austrian Science Fund (FWF) under Grant no. P24736-B23.
2144 | Analyst, 2013, 138, 2134–2145
Paper
We greatly appreciate the generous support of the government
of Vorarlberg, Austria.
References
1 A. Amann, M. Corradi, P. Mazzone and A. Mutti, Expert Rev.
Mol. Diagn., 2011, 11, 207–217.
2 A. Amann and D. Smith, Breath analysis for clinical diagnosis
and therapeutic monitoring, World Scientic, New Jersey,
2005.
3 W. Miekisch, J. K. Schubert and G. F. Noeldge-Schomburg,
Clin. Chim. Acta, 2004, 347, 25–39.
4 A. Amann, G. Poupart, S. Telser, M. Ledochowski, A. Schmid
and S. Mechtcheriakov, Int. J. Mass Spectrom., 2004, 239,
227–233.
5 A. Bajtarevic, C. Ager, M. Pienz, M. Klieber, K. Schwarz,
M. Ligor, T. Ligor, W. Filipiak, H. Denz, M. Fiegl, W. Hilbe,
W. Weiss, P. Lukas, H. Jamnig, M. Hackl, A. Haidenberger,
B. Buszewski, W. Miekisch, J. Schubert and A. Amann,
BMC Cancer, 2009, 9, 348.
6 D. Poli, P. Carbognani, M. Corradi, M. Goldoni, O. Acampa,
B. Balbi, L. Bianchi, M. Rusca and A. Mutti, Respir. Res., 2005,
6, 71.
7 M. Phillips, N. Altorki, J. H. Austin, R. B. Cameron,
R. N. Cataneo, R. Kloss, R. A. Maxeld, M. I. Munawar,
H. I. Pass, A. Rashid, W. N. Rom, P. Schmitt and J. Wai,
Clin. Chim. Acta, 2008, 393, 76–84.
8 A. Amann, M. Ligor, T. Ligor, A. Bajtarevic, C. Ager, M. Pienz,
H. Denz, M. Fiegl, W. Hilbe, W. Weiss, P. Lukas, H. Jamnig,
M. Hackl, A. Haidenberger, A. Sponring, W. Filipiak,
W. Miekisch, J. Schubert and B. Buszewski, Magazine of
European Medical Oncology, 2010, vol. 3, pp. 106–112.
9 M. Phillips, J. P. Boehmer, R. N. Cataneo, T. Cheema,
H. J. Eisen, J. T. Fallon, P. E. Fisher, A. Gass, J. Greenberg,
J. Kobashigawa, D. Mancini, B. Rayburn and M. J. Zucker,
J. Heart Lung Transplant., 2004, 23, 701–708.
10 M. Phillips, R. N. Cataneo, C. Saunders, P. Hope, P. Schmitt
and J. Wai, J. Breath Res., 2010, 4, 026003.
11 J. Scholpp, J. K. Schubert, W. Miekisch and K. Geiger, Clin.
Chem. Lab. Med., 2002, 40, 587–594.
12 S. Kanoh, H. Kobayashi and K. Motoyoshi, Chest, 2005, 128,
2387–2392.
13 J. Rudnicka, P. Mochalski, A. Agapiou, M. Statheropoulos,
A. Amann and B. Buszewski, Anal. Bioanal. Chem., 2010,
398, 2031–2038.
14 P. Mochalski, A. Agapiou, M. Statheropoulos and A. Amann,
Analyst, 2012, 137, 3278–3285.
15 P. Mochalski, K. Krapf, C. Ager, H. Wiesenhofer, A. Agapiou,
M. Statheropoulos, D. Fuchs, E. Ellmerer, B. Buszewski and
A. Amann, Toxicol. Mech. Methods, 2012, 22, 502–511.
16 P. Mochalski, M. Buszewska, A. Agapiou, M. Statheropoulos,
B. Buszewski and A. Amann, Chromatographia, 2012, 75,
41–46.
17 R. Huo, A. Agapiou, V. Bocos-Bintintan, L. J. Brown,
C. Burns, C. S. Creaser, N. A. Devenport, B. Gao-Lau,
C. Guallar-Hoyas, L. Hildebrand, A. Malkar, H. J. Martin,
V. H. Moll, P. Patel, A. Ratiu, J. C. Reynolds, S. Sielemann,
This journal is ª The Royal Society of Chemistry 2013
Paper
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
R. Slodzynski, M. Statheropoulos, M. A. Turner, W. Vautz,
V. E. Wright and C. L. Thomas, J. Breath Res., 2011, 5, 046006.
S. A. Bartels and M. J. VanRooyen, Lancet, 2012, 379,
748–757.
B. Buszewski, A. Ulanowska, T. Ligor, N. Denderz and
A. Amann, Biomed. Chromatogr., 2008, 23, 551–556.
M. Ligor, T. Ligor, A. Bajtarevic, C. Ager, M. Pienz,
M. Klieber, H. Denz, M. Fiegl, W. Hilbe, W. Weiss,
P. Lukas, H. Jamnig, M. Hackl, B. Buszewski, W. Miekisch,
J. Schubert and A. Amann, Clinical chemistry and laboratory
medicine: CCLM/FESCC, 2009, vol. 47, pp. 550–560.
T. Ligor, M. Ligor, A. Amann, C. Ager, M. Bachler, A. Dzien
and B. Buszewski, J. Breath Res., 2008, 2, 046006.
I. Kushch, B. Arendacka, S. Stolc, P. Mochalski, W. Filipiak,
K. Schwarz, L. Schwentner, A. Schmid, A. Dzien,
M. Lechleitner, V. Witkovsky, W. Miekisch, J. Schubert,
K. Unterkoer and A. Amann, Clin. Chem. Lab. Med., 2008,
46, 1011–1018.
K. Sexton, J. L. Adgate, T. R. Church, D. L. Ashley,
L. L. Needham, G. Ramachandran, A. L. Fredrickson and
A. D. Ryan, Environ. Health Perspect., 2005, 113, 342–349.
D. L. Ashley, M. A. Bonin, F. L. Cardinali, J. M. McCraw and
J. V. Wooten, Clin. Chem., 1994, 40, 1401–1404.
C. Jia, X. Yu and W. Masiak, Sci. Total Environ., 2012, 419,
225–232.
F. Brugnone, L. Perbellini, G. B. Faccini, F. Pasini,
G. Maranelli, L. Romeo, M. Gobbi and A. Zedde, Int. Arch.
Occup. Environ. Health, 1989, 61, 303–311.
F. Brugnone, L. Perbellini, G. B. Faccini, F. Pasini, B. Danzi,
G. Maranelli, L. Romeo, M. Gobbi and A. Zedde, Am. J. Ind.
Med., 1989, 16, 385–399.
L. Perbellini, A. Princivalle, M. Cerpelloni, F. Pasini and
F. Brugnone, Int. Arch. Occup. Environ. Health, 2003, 76,
461–466.
P. Houeto, J. R. Hoffman, P. Got, B. Dang Vu and F. J. Baud,
Hum. Exp. Toxicol., 1997, 16, 658–661.
D. M. Chambers, J. M. Ocariz, M. F. McGuirk and
B. C. Blount, Environ. Int., 2011, 37, 1321–1328.
W. Miekisch, J. K. Schubert, D. A. Vagts and K. Geiger, Clin.
Chem., 2001, 47, 1053–1060.
W. Miekisch, P. Fuchs, S. Kamysek, C. Neumann and
J. K. Schubert, Clin. Chim. Acta, 2008, 395, 32–37.
M. E. O'Hara, T. H. Clutton-Brock, S. Green and
C. A. Mayhew, J. Breath Res., 2009, 3, 027005.
M. E. O'Hara, T. H. Clutton-Brock, S. Green, S. O'Hehir and
C. A. Mayhew, Int. J. Mass Spectrom., 2009, 281, 92–96.
A. Cailleux, M. Cogny and P. Allain, Biochem. Med. Metab.
Biol., 1992, 47, 157–160.
This journal is ª The Royal Society of Chemistry 2013
Analyst
36 J. King, P. Mochalski, K. Unterkoer, G. Teschl, M. Klieber,
M. Stein, A. Amann and M. Baumann, Biochem. Biophys.
Res. Commun., 2012, 423, 526–530.
37 N. Li, C. Deng, X. Yin, N. Yao, X. Shen and X. Zhang, Anal.
Biochem., 2005, 342, 318–326.
38 C. Deng, N. Li and X. Zhang, J. Chromatogr., B: Anal. Technol.
Biomed. Life Sci., 2004, 813, 47–52.
39 J. King, P. Mochalski, A. Kupferthaler, K. Unterkoer,
H. Koc, W. Filipiak, S. Teschl, H. Hinterhuber and
A. Amann, Physiol. Meas., 2010, 31, 1169–1184.
40 J. King, A. Kupferthaler, K. Unterkoer, H. Koc, S. Teschl,
G. Teschl, W. Miekisch, J. Schubert, H. Hinterhuber and
A. Amann, J. Breath Res., 2009, 3, 027006.
41 H. Koc, J. King, G. Teschl, K. Unterkoer, S. Teschl,
P. Mochalski, H. Hinterhuber and A. Amann, J. Breath Res.,
2011, 5, 037102.
42 J. King, H. Koc, K. Unterkoer, P. Mochalski,
A. Kupferthaler, G. Teschl, S. Teschl, H. Hinterhuber and
A. Amann, J. Theor. Biol., 2010, 267, 626–637.
43 A. Amann, W. Miekisch, J. Pleil, T. Risby and J. Schubert, Eur.
Respir. Monogr., 2010, 49, 96–114.
44 W. Filipiak, A. Filipiak, C. Ager, H. Wiesenhofer and
A. Amann, J. Breath Res., 2012, 6, 027107.
45 Y. Gong, I. Y. Eom, D. W. Lou, D. Hein and J. Pawliszyn, Anal.
Chem., 2008, 80, 7275–7282.
46 M. Mieth, S. Kischkel, J. K. Schubert, D. Hein and
W. Miekisch, Anal. Chem., 2009, 81, 5851–5857.
47 W. Huber, Accredit. Qual. Assur., 2003, 8, 213–217.
48 K. Schwarz, A. Pizzini, B. Arendacka, K. Zerlauth, W. Filipiak,
A. Schmid, A. Dzien, S. Neuner, M. Lechleitner, S. SchollBurgi, W. Miekisch, J. Schubert, K. Unterkoer,
V. Witkovsky, G. Gastl and A. Amann, J. Breath Res., 2009,
3, 027003.
49 W. Filipiak, V. Ruzsanyi, P. Mochalski, A. Filipiak,
A. Bajtarevic, C. Ager, H. Denz, W. Hilbe, H. Jamnig,
M. Hackl, A. Dzien and A. Amann, J. Breath Res., 2012, 6,
036008.
50 S. Smith, H. Burden, R. Persad, K. Whittington, B. de Lacy
Costello, N. M. Ratcliffe and C. S. Probert, J. Breath Res.,
2008, 2, 037022.
51 H. G. Wahl, A. Hoffmann, D. Lu and H. M. Liebich,
J. Chromatogr., A, 1999, 847, 117–125.
52 D. Gelmont, R. A. Stein and J. F. Mead, Biochem. Biophys. Res.
Commun., 1981, 99, 1456–1460.
53 P. Mochalski, J. King, A. Kupferthaler, K. Unterkoer,
H. Hinterhuber and A. Amann, Int. J. Toxicol., 2012, 31,
267–275.
54 T. S. Dibble, J. Phys. Chem. A, 1999, 103, 8559–8565.
Analyst, 2013, 138, 2134–2145 | 2145