Spectrophotometric

A  simple  UV-Visible  spectrophotometric  method  has  been
developed for the determination of Atorvastatin in its pure form as
well as pharmaceutical dosage form using Methyl Orange reagent.
The  method  is  based  on  the  measurement  of  absorbance  of
Atorvastatin in methanol at 410 nm. The Beer’s law is obeyed
over  the  linear  range  50-300μg  /ml  of  Atorvastatin.  All  the
variables were studied to optimize the reaction conditions. No
interference  was  observed  in  the  presence  of  common
pharmaceutical excipients. The validity of the method was tested
by analyzing the drug in its pharmaceutical preparations. Good
recoveries were also obtained. Assay for the tablet preparation was
performed using UV-Visible spectrophotometric method and the
results were found to be within acceptable limits.

The determination of saccharide is widespread and has led to the development of numerous analytical techniques for measuring its concentrations. Analytical tool with various applications in different fields are tedious and have time-consuming protocols ranging from food analysis to biology. The overall purpose of this research is to develop easy methods for analyzing reducing sugars or saccarides. The most abundant monosaccharide in nature Dglucose sometimes referred to as dextrose in our research its shows a peak difference of 1nm as one water molecule is always loosely attached to dextrose ring structure. In this article it is seen that DNSA methods has advantage of its simplicity, low cost, sensitivity and adoptable during handling the analysis of a large number of samples at a time.

Wang, LK and Wang, MHS (2022). Oil and grease determination, solvent hazards and waste disposal when using trichloroethane (methyl chloroform) for extraction; In:  “Evolutionary Progress in Science, Technology, Engineering, Arts and Mathematics (STEAM)”, Wang, LK and Tsao, HP (eds.), 4 (6C), STEAM-VOL4-NUM6C-JUNE202. 54 pages. June 2022, Lenox Institute Press, Massachusetts, USA. https://doi.org/10.17613/w34y-0r55  .........: ABSTRACT:  A spectrophotometric procedure has been developed for determination of hydrocarbons, vegetable oils, animal fats, waxes, soaps, greases and related oily organic matter in aqueous phase.  The water sample is acidified to  a low pH (less than or equal to 2) and extracted with  trichloroethane (methyl chloroform). Under controlled conditions, the oil  and grease are extractable into the selected organic solvent, where the intensity of yellow color is proportional to the oil and grease concentration.  The color in the selected organic solvent  (methyl chloroform) is measured by spectrophotometry at recommended wavelengths. The new analytical method uses  a visible spectrophotometer or a filter photometer, which is available in almost any water quality laboratories. The oil and grease concentration as low as 0.1 mg/L  can be quantitatively measured,  provided that a quartz cell with light path length of 5 cm or longer is used. Colorimetry  (instead of spectrophotometry) can also be used if a colorimeter is properly calibrated or color charts are properly developed.  Selection of an appropriate organic solvent for oil and grease analysis is discussed in terms of  chemist contact risk and hazardous solvent disposal.  Current Standard Methods 5520B, 5520D, 5520E, and 5520G for oil and grease analysis adopt n-hexane for solvent extraction.  The authors compare the selected solvent with n-hexane and conclude that trichloroethane (methyl chloroform) is better than n-hexane considering the safety of both the laboratory workers and the laboratory although trichloroethane is an ozone-depleting substance (ODS).  Solvent recycle and/or proper laboratory waste management will eliminate the opportunity of ODS release to the environment.

The complexation reaction between salen (Bis(salicylidene)ethylenediamine) and Cu(II) cations in methanol (MeOH), 2-propanol (2-PrOH), acetonitrile (AN), tetrahydrofuran (THF), and chloroform (CHCl3) as nonaqueous solvents at 25o C has been investigated. The stoichiometry and formation constants of complexes have been determined spectrophotometrically and conductometrically by method of continuous variations and mole ration method. The stoichiometry of Cu(II)-salen complexes in all solvents were 1:1 (ML) type using the two methods. By method of continuous variation, chloroform > 2-propanol > methanol ~ acetonitrile ~ tetrahydrofuran. However, by mole ratio method, the order of stability was as follows: chloroform ~ tetrahydrofuran > 2-propanol > methanol ~ acetonitrile. The resulting average of pKf values in each solvent using the two spectrophotometric methods was as follows: 7.40, 6.89, 6.8, 6.22, and 6.18 for chloroform, 2-propanol, tetrahydrofuran, acetonitrile, and ...

Four methods have been developed for the simultaneous determination of phenylephrine hydrochloride and chlorpheniramine maleate without previous separation. In the first method both drugs are determined using first derivative UV spectrophotometry, with zero-crossing measurement. The second method depends on first derivative of the ratios spectra. The third method describes the use of multivariate spectrophotometric calibration for the simultaneous determination of