ABSTRACT
OBJECTIVE: To establish a method for the determination of formic acid in urine by automatic headspace-gas chromatography-mass spectrometry. METHODS: The urine sample was added with 3 mL 15.00%(V/V) sulfuric acid ethanol and heated in an automatic headspace sampler. The formic acid and ethanol underwent an esterification reaction to produce ethyl formate which was separated by gas chromatographic column and detected by mass spectrometer. The quantification was based on external standard method. RESULTS: The linear range of the method was 2.93-97.60 mg/L, with the regression equation correlation coefficient of 0.999 5. The detection limit was 0.65 mg/L and the minimum quantitative limit was 2.17 mg/L, with the recoveries of 95.61%-106.47%. The within-run relative standard deviation(RSD) ranged from 2.52% to 8.05% and the between-run RSD ranged from 6.58% to 8.42%. CONCLUSION: The method has simple pretreatment, good specificity, high precision and has little interference. It is suitable for large scale rapid determination of formic acid in urine in occupational contact population, patients with acute methanol poisoning and general population.
ABSTRACT
OBJECTIVE: To establish a detection method for 1-bromopropane in human urine by headspace gas chromatography-mass spectrometry( GC-MS). METHODS: A 4. 00 m L portion of the urine sample was placed in a 15. 00 m L headspace vial and 20. 00 μL of 1-bromobutane internal standard solution( 204. 200 mg / L mass concentration) was added.The bottle cap was immediately sealed. The sample was heated to 80 ℃ with an equilibrium time of 20 minutes in the headspace device. The vapor in the headspace vial was separated by GSBP-FFAP( 30. 00 m × 0. 25 mm × 0. 25 μm)capillary chromatography column and the ion was used to carry out quantitative determination of 1-bromopropane in human urine. RESULTS: The good linearity range of 1-bromopropan mass concentration was 0. 025-1. 012 mg / L, and the correlation coefficient was 0. 999 8. The detection limit was 7. 5 μg / L( urine sample volume,4. 00 m L) and the limit of quantitation was 25. 0 μg / L( urine sample volume,4. 00 m L). The relative standard deviation( RSD) of within-run precision was 2. 61%-4. 08%,and the RSD of between-run precision was 2. 79%-6. 25%. The average recovery rate was99. 34%-105. 94%. CONCLUSION: The method of determining 1-bromopropane in human urine by headspace GC-MS has the features of high sensitivity,good linear relationship,low interference,good precision and easy operation,which is suitable for detecting 1-bromopropane mass concentration in human urine.