A rapid on-line solid phase extraction/liquid chromatography/tandem mass spectrometry (SPE/LC/MS/... more A rapid on-line solid phase extraction/liquid chromatography/tandem mass spectrometry (SPE/LC/MS/MS) method using restricted access material (RAM) was developed for the simultaneous determination of eight organophosphorus triesters in untreated human blood plasma. In a process involving column-switching techniques, the analytes were enriched on the RAM column, separated using a C-18 analytical column and detected with LC/MS. Tandem mass spectrometry was used to characterize and quantify the analytes. To elucidate the fragmentation pathway of a number of the analytes, MS3 experiments using an ion trap mass spectrometer were performed. The matrix effects associated with using APCI and ESI interfaces were investigated. The recoveries obtained were in the range 60-92% (R.S.D.<6%), with estimated detection limits between 0.2 and 1.8 ng/ml of plasma, and the total analysis time was 27 min.
ABSTRACT An analytical method for determining nitroaromatic explosives in vapour phases is presen... more ABSTRACT An analytical method for determining nitroaromatic explosives in vapour phases is presented. Samples were collected by pumping air through glass fibre filters and polyurethane foam adsorbents, and an on-line extraction system combining supercritical fluid extraction (SFE) and high-performance liquid chromatography (HPLC) was developed. This allows analytes to be transferred from the adsorbent to the HPLC system via a porous graphitic carbon trap. When using gradient elution with a suitable mobile phase, most of the nitroaromatic isomers tested were separated. The proposed method is fully automated, allows a complete analysis to be processed in less than 30 min, and it is compatible with most of the organic solvents commonly used as SFE modifiers or additives. The method has been applied to the analysis of real samples obtained from headspace sampling of military-grade 2,4,6-trinitrotoluene and has been shown to constitute a promising alternative for assessing whether areas are mined in landmine-clearing operations.
A new LC-MS method for the determination and characterization of three groups of commonly used or... more A new LC-MS method for the determination and characterization of three groups of commonly used organic explosives (nitroaromatic compounds, cyclic nitroamines and nitrate esters) was developed using a porous graphitic carbon (PGC) (Hypercarb) column. Twenty-one different explosive-related compounds--including 2,4,6-trinitrotoluene, its by-products and its degradation products--were chromatographically separated in a single analysis. This efficient separation facilitates the identification of the manufacturer of the explosive using the identified analytes as a fingerprint. A final, conclusive identification of the analytes can be obtained using LC-MS equipped with an atmospheric pressure chemical ionization (APCI) interface. Solvent effects on chromatographic behaviour were investigated, as were the effects of solvent mixtures and mobile phase additives. The number and the relative positions of the nitro groups within analyte molecules influence their order of elution; these effects were investigated. The data thus generated can be interpreted to support a hypothesis concerning the retention mechanism of nitro-containing compounds when using PGC. Limits of detection ranged from 0.5 to 41.2 ng. The new methodology described herein improves the sensitivity and selectivity of explosive detection. The effectiveness of the method is demonstrated by the analysis of soil samples containing explosives residue from test fields in Sweden and Afghanistan.
International Journal of Environmental Analytical Chemistry, 2003
New separation/detection procedures by reversed-phase HPLC coupled with UV and fluorescence detec... more New separation/detection procedures by reversed-phase HPLC coupled with UV and fluorescence detection have been developed for the determination of organic admixtures of the sulphonated melamines-formaldehyde condensates (SMFC) and lignosulphonates (LS) type in environmental samples (drinking and ground waters), as well as in concrete leachates. The developed method permitted to reach detection limits in the 0.05-0.3 µg range (as injected amount).
This paper explores the use of C18 solid-phase extraction membranes for sampling very low concent... more This paper explores the use of C18 solid-phase extraction membranes for sampling very low concentrations of nitroaromatic compounds in the atmosphere. After sampling, analytes trapped in the membrane are desorbed on-line directly by a chromatographic mobile phase. The analytes are then separated onto a porous graphitic carbon (PGC) HPLC column. Finally, they are analyzed by an LC-MS/MS detector equipped with an atmospheric pressure chemical ionization (APCI) interface. The method was validated by controlled exposure of the membranes to standard gaseous mixtures of 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (2,4-DNT). The developed method was fully characterized, and no breakthrough was observed when sampling volumes up to 9.2 m3. Analyses of membranes following medium- and long-term storage demonstrated that samples could be stored on the C18 membranes without degradation or losses. In addition, the results obtained with this technique were compared with those obtained by a gas chromatographic method in which analytes were collected on Tenax TA and thermally desorbed. The developed method allows sampling at flow rates of 15 L/min and has method detection limits in the femtogram/liter range, with a relative standard deviation lower than 10%. An additional advantage of this method is that it separates most of the TNT and DNT isomers, as demonstrated by applying the method to the analysis of headspace over military-grade TNT explosives.
Manufacturing of textile consumer goods involve a multitude of chemicals during the entire produc... more Manufacturing of textile consumer goods involve a multitude of chemicals during the entire production chain. In order to investigate the release of harmful compounds from the end products, a sensit ...
A molecularly imprinted polymer (MIP) that selectively retains diphenyl phosphate was prepared us... more A molecularly imprinted polymer (MIP) that selectively retains diphenyl phosphate was prepared using a structural analogue, ditolyl phosphate, as a template. Diphenyl phosphate is a degradation product of the flame retardant additive, triphenyl phosphate. The latter has been shown to be a common airborne contaminant in indoor environments and to be emitted from various goods such as video display units.
A rapid on-line solid phase extraction/liquid chromatography/tandem mass spectrometry (SPE/LC/MS/... more A rapid on-line solid phase extraction/liquid chromatography/tandem mass spectrometry (SPE/LC/MS/MS) method using restricted access material (RAM) was developed for the simultaneous determination of eight organophosphorus triesters in untreated human blood plasma. In a process involving column-switching techniques, the analytes were enriched on the RAM column, separated using a C-18 analytical column and detected with LC/MS. Tandem mass spectrometry was used to characterize and quantify the analytes. To elucidate the fragmentation pathway of a number of the analytes, MS3 experiments using an ion trap mass spectrometer were performed. The matrix effects associated with using APCI and ESI interfaces were investigated. The recoveries obtained were in the range 60-92% (R.S.D.<6%), with estimated detection limits between 0.2 and 1.8 ng/ml of plasma, and the total analysis time was 27 min.
ABSTRACT An analytical method for determining nitroaromatic explosives in vapour phases is presen... more ABSTRACT An analytical method for determining nitroaromatic explosives in vapour phases is presented. Samples were collected by pumping air through glass fibre filters and polyurethane foam adsorbents, and an on-line extraction system combining supercritical fluid extraction (SFE) and high-performance liquid chromatography (HPLC) was developed. This allows analytes to be transferred from the adsorbent to the HPLC system via a porous graphitic carbon trap. When using gradient elution with a suitable mobile phase, most of the nitroaromatic isomers tested were separated. The proposed method is fully automated, allows a complete analysis to be processed in less than 30 min, and it is compatible with most of the organic solvents commonly used as SFE modifiers or additives. The method has been applied to the analysis of real samples obtained from headspace sampling of military-grade 2,4,6-trinitrotoluene and has been shown to constitute a promising alternative for assessing whether areas are mined in landmine-clearing operations.
A new LC-MS method for the determination and characterization of three groups of commonly used or... more A new LC-MS method for the determination and characterization of three groups of commonly used organic explosives (nitroaromatic compounds, cyclic nitroamines and nitrate esters) was developed using a porous graphitic carbon (PGC) (Hypercarb) column. Twenty-one different explosive-related compounds--including 2,4,6-trinitrotoluene, its by-products and its degradation products--were chromatographically separated in a single analysis. This efficient separation facilitates the identification of the manufacturer of the explosive using the identified analytes as a fingerprint. A final, conclusive identification of the analytes can be obtained using LC-MS equipped with an atmospheric pressure chemical ionization (APCI) interface. Solvent effects on chromatographic behaviour were investigated, as were the effects of solvent mixtures and mobile phase additives. The number and the relative positions of the nitro groups within analyte molecules influence their order of elution; these effects were investigated. The data thus generated can be interpreted to support a hypothesis concerning the retention mechanism of nitro-containing compounds when using PGC. Limits of detection ranged from 0.5 to 41.2 ng. The new methodology described herein improves the sensitivity and selectivity of explosive detection. The effectiveness of the method is demonstrated by the analysis of soil samples containing explosives residue from test fields in Sweden and Afghanistan.
International Journal of Environmental Analytical Chemistry, 2003
New separation/detection procedures by reversed-phase HPLC coupled with UV and fluorescence detec... more New separation/detection procedures by reversed-phase HPLC coupled with UV and fluorescence detection have been developed for the determination of organic admixtures of the sulphonated melamines-formaldehyde condensates (SMFC) and lignosulphonates (LS) type in environmental samples (drinking and ground waters), as well as in concrete leachates. The developed method permitted to reach detection limits in the 0.05-0.3 µg range (as injected amount).
This paper explores the use of C18 solid-phase extraction membranes for sampling very low concent... more This paper explores the use of C18 solid-phase extraction membranes for sampling very low concentrations of nitroaromatic compounds in the atmosphere. After sampling, analytes trapped in the membrane are desorbed on-line directly by a chromatographic mobile phase. The analytes are then separated onto a porous graphitic carbon (PGC) HPLC column. Finally, they are analyzed by an LC-MS/MS detector equipped with an atmospheric pressure chemical ionization (APCI) interface. The method was validated by controlled exposure of the membranes to standard gaseous mixtures of 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (2,4-DNT). The developed method was fully characterized, and no breakthrough was observed when sampling volumes up to 9.2 m3. Analyses of membranes following medium- and long-term storage demonstrated that samples could be stored on the C18 membranes without degradation or losses. In addition, the results obtained with this technique were compared with those obtained by a gas chromatographic method in which analytes were collected on Tenax TA and thermally desorbed. The developed method allows sampling at flow rates of 15 L/min and has method detection limits in the femtogram/liter range, with a relative standard deviation lower than 10%. An additional advantage of this method is that it separates most of the TNT and DNT isomers, as demonstrated by applying the method to the analysis of headspace over military-grade TNT explosives.
Manufacturing of textile consumer goods involve a multitude of chemicals during the entire produc... more Manufacturing of textile consumer goods involve a multitude of chemicals during the entire production chain. In order to investigate the release of harmful compounds from the end products, a sensit ...
A molecularly imprinted polymer (MIP) that selectively retains diphenyl phosphate was prepared us... more A molecularly imprinted polymer (MIP) that selectively retains diphenyl phosphate was prepared using a structural analogue, ditolyl phosphate, as a template. Diphenyl phosphate is a degradation product of the flame retardant additive, triphenyl phosphate. The latter has been shown to be a common airborne contaminant in indoor environments and to be emitted from various goods such as video display units.
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