The recovery was 93%-117%, intraday accuracy, expressed as the deviation from the nominal value, was 92.7%-103.0%, and intraday precision, expressed as the relative standard deviation (RSD), was 1.3%-4.7%. For each metabolite, the limits of detection and quantification were 3 mg/L and 10 mg/L, respectively. ResultsĬalibration curves showed linearity in the concentration range of 10-1000 mg/L for each metabolite, with correlation coefficients >0.999. The accuracy of the proposed method was confirmed by analyzing a ClinChek ®-Control for occupational medicine (RECIPE Chemicals +Instruments GmbH). The proposed method was validated according to the US Food and Drug Administration guidance. The four metabolites were directly methyl-esterified with 2,2-dimethoxypropane and analyzed using GC-MS. Allow the solvent to evaporate from the Na2SO, then place i to evaporate from the Na2SO, then place it into the solid waste container.The purpose of this study was to develop a simple and accurate gas chromatography-mass spectrometry (GC-MS) method for simultaneous determination of four urinary metabolites from four organic solvents, that is, hippuric acid (HA) from toluene, methylhippuric acid (MHA) from xylene, and mandelic acid (MA) and phenylglyoxylic acid (PGA) from styrene or ethylbenzene for biological monitoring. Clean up: The aqueous solutions from washing steps can be diluted solutions from washing steps can be diluted with water and drained into the sink. Which diastereomer (meso or (+)) is the major product of the benzil reduction with borohydride? What is the ratio of the major product to the minor one? Explain the stereoselectivity of the borohydride reduction. When the crystals are dry weigh your product, measure mp and submit sample for NMR analysis (1 sample/section). Filter the solution into a clean dry Erlenmeyer flask and let the solvent evaporate, Evaporation of the solvent yields the crude product. Separate the organic layer and dry it over Na2SO4 for at least 10 min. Wash the organic phase successively with H2O (10 mL) and saturated NaHCO, (10 mL) (organic layer will be on the bottom). Add CH CL (15 mL) to the reaction mixture and transfer solution into a small se flask with additional CH2CL (10 ml) and place it in the separatory funnel as well.
Cork the flask and stir the ((5 mg - one-two crystals) and a magnet bar into 25 mL Erlenmeyer flack mixture at room temperature for 1 hour. Transcribed image text: Experimental Section: O Place hydrobenzoin (200 mg), 2,2-dimethoxypropane (2.5 mL), P-tolu 2.2-dimethoxypropane (2.5 mL), P-toluenesulfonic acid monohydrate a magnet bar into 25 mL Erlenmeyer flask.
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