Determination of formic acid in urine by automatic headspace-gas chromatography-mass spectrometry / 中国职业医学

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.

Study on quantification method of non-starch polysaccharides in Dendrobium catenatum / 中国中药杂志

The non-starch polysaccharides,mainly composed of glucomannans,are the major bioactive compounds in Dendrobium catenatum. In order to evaluate the quality of the medicinal materials and guide the production and processing,a quantification method of non-starch polysaccharides was established by stems of D. catenatum C15 strain collected from the pear epiphytic cultivation. The non-starch polysaccharides were obtained by " water extraction,α-amylase pretreatment,and alcohol precipitation once" method. The contents of starches,non-starch polysaccharides and monosaccharides were analyzed. In addition,the system suitability was tested. Compared with method of the Chinese Pharmacopoeia( 2015 edition),the contents of total polysaccharides,glucose,and mannose were decreased by 20. 9%,58. 8% and 1. 6% respectively. The method effectively digested starch and retained non-starch polysaccharides,and the analysis result was accurate and repeatable. Therefore,it is suitable for the content measurement of non-starch polysaccharides of D. catenatum. Furthermore,it could be an alternative method for quality control of D. catenatum and a reference in the determination of non-starch polysaccharides in other starch-containing medicinal materials.

Reform Microbiology Experiment Teaching Methods, Enhance the Students’ Comprehensive Abilities / 微生物学通报

In order to cultivate the students’ abilities of thinking and practicing and enhance their comprehensive abilities in microbiology experiment, the authors try to search for some new teaching ways and assessment methods in microbiology experimental teaching and also attempt to make some improvement in the textbook and adjustment in teaching schedule so as to develop the students into specialized talents.