中文摘要：

目的探讨不同温度、不同保存时间及反复冻融对尿中各形态砷稳定性的影响。方法于2011年3月，采集：名健康志愿者的尿液样品。采用氢化物发生一冷阱捕集一原子吸收（HG—coldtrap—AAS）法检测不同保存条件[尿样分别置F室温（25℃）和4、-20、-80℃冰箱中继续避光保存1、3个月]和反复冻融（冻融条件：-20、-80℃冻存至少1d，室温2h弹冻，再次放入冰箱）3次后尿样中各形态砷[无机砷（iAs）、一甲基砷（MMA）和二甲基砷（DMA）、三甲基砷（TMA）]的浓度。每欠检测前解冻，并设立对照。结果仅25℃条件下保存3个月样品中DMA浓度低于对照，差异有统计学意义（P〈0．05）；毒他保存条件下尿样中各形态砷的浓度与对照比较，差异均无统计学意义。在低温（-20、-80℃）条件下反复冻融3次后畏样中各形态砷的浓度与对照比较，差异均无统计学意义。结论低温（4、-20、-80℃）保存3个月内以及冻融3次的尿羊中各形态砷浓度仍较为稳定。

英文摘要：

Objective To explore the effects of different storage conditions and freezing-thawing on the stability of urinary arsenic species. Methods In March 2011 ,the urine samples collecteded from eight healthy volunteers were kept in different storage conditions [urinary samples were put at room temperature （25℃） and 4,-20,-80℃ in dark place for 1 or 3 months respectively] and repeated freezing-thawing （frozen at -20,-80℃ at least one day and thawed at room temperature for 2 hours, then put back to refrigerator for three times）. Arsenic species in the urine samples were detected with hydride generation atomic absorption spectroscopy. The sample were thawed before detection every time,and control group was set up. Results The DMA level in urinary samples stored at 25℃ after 3 months was significantly lower than that in control group （P〈0.05）. There were no significant differences for the levels of urinary arsenic species in other storage conditions compared with control group. After three times fo freezing-thawing cycles at -20 and -80℃ ,no differences were found in the concentration of urinary arsenic species compared with control group. Conclusion The levels of arsenic species are stable after they were stored at low temperature （4,-20 and -80℃） for 3 months or through three times of freezing-thawing cycles.