Preparation of specimens for external quality control of urinary biological monitoring

制备未接触过有机溶剂的正常人尿液和含有人尿液主要成分的青蒿素尿，作为质量控制调查的样本。将不同浓度的马尿酸、甲基马尿酸和扁桃酸掺入正常尿液和人造尿液中。将部分样品冷冻干燥后用于质量控制研究，然后将样品在30 ℃、4 ℃和-20 ℃下保存1周、2周和4周，用高效液相色谱法分析上述三种酸在保存期间的浓度变化。在30 ℃下储存1周、1 ℃下储存2周和-20 ℃下储存4周后，每种酸的平均浓度为储存前的97%或更高。这三种酸在低温下均较稳定，其中扁桃酸最稳定。的cr ...更多信息 在30 ℃和4 ℃的储存条件下，与三种酸相比，依地奈德的稳定性较差。在正常尿液中掺入高浓度和低浓度的三种酸的情况下，在30 ℃下储存1周和4 ℃下储存后，每种酸的平均浓度为储存前的99%或更高，20 ℃下冷冻干燥4周。当人工和正常尿液中加入高浓度和低浓度的三种酸时，在25 ℃下储存后，每种酸的平均浓度约为在干燥人工尿液中储存前的100%，更多的是在储存在干燥的人类尿液中之前。接触低浓度甲苯和二甲苯混合物的工人尿液中的马尿酸和甲基马尿酸在-20 ° C冷冻条件下可保持6个月不变。制备用于外部质量控制的样本中所含的尿液溶剂代谢物在低温下邮寄后被证明是稳定的。少

Urines from normal human subjects who had not been exposed to organic solvents and artficial urines containing major components of human urine were prepared as specimens for the survey of quality control. Various concentrations of the hippuric acid, methylhippuric acid and mandelic acid were spiked into the normal and artificial urines. Some of specimens were freeze-dried and used for quality control studies.Thereafter, the specimens were kept at 30ﾟC,4ﾟC and -20ﾟC for 1,2 and 4 weeks, and the changes in concentrations of above described three acids during storage were analyzed by high performance liquid chromatography.In the case of artificial urines spiked with the three acids, the average concentration of each acid after storage was 97 per cent or more of that before storage under the condition at 30ﾟC for 1 week, 1ﾟC for 2 week and -20ﾟC for 4 weeks. The three acids were stable when they were kept at lower temperature and the mandelic acid was the most stable one among them. The cr … More eatinine was less stable compared to the three acids under the storing condition at 30ﾟC and 4ﾟC.In the case of normal urine spiked with three acids at high and low concentrations, the average concentration of each acid after storage was 99 per cent or more of that before storage under the condition at 30ﾟC for 1 week and 4ﾟC and -20ﾟC for 4 weeks.When artificial and normal urines spiked with three acids at high and low concentrations were freezedried, the average concentration of each acid after storage at 25ﾟC was approximately 100 per cent of that before storage in dried artificial urine and was 99 per cent or more of those before storage in dried human urine. The hippuric acid and methylhippuric acid in the urine of workers exposed to low concentrations of mixed toluene and xylenes could be kept without change for 6 months under the freezing condition at -20ﾟC.Urinaly metabolites of solvents contained in the specimens prepared for external quality control were proved to be stable after mailing at low temperature. Less