尿碘测定样品的稳定性观察

Observation on stability of urine sample for iodine determination

目的观察用于碘测定的尿样稳定性,提供正确的尿样保存条件和时间。方法采用修订后的尿碘测定新方法——过硫酸铵消化尿样的方法检测不同保存时间及不同保存条件下尿样的碘水平。结果室温酸化条件下,从保存30d起尿碘测定值与基础值比较其相对偏差值>10%,其他各种保存条件的尿碘测定值的相对偏差值均<10%;室温和4℃两种保存温度下,酸化尿样碘测定值明显高于未酸化样品(t=-2.23、t=-2.74,P<0.05),-20℃保存时酸化对尿碘测定值无明显影响(t=-1.19,P>0.05);保存温度对尿碘测定值(无论尿样酸化与否)影响不大(F不酸化=0.051、F酸化=0.981,P>0.05)。结论室温不酸化条件和4℃(不酸化和酸化)条件下尿样可保存2个月,-20℃(不酸化和酸化)条件尿样可保存4个月。为减少不必要的工作麻烦,尿样无须酸化处理。

Objective To set up a proper condition and duration for storage of urine sample by observing stability of urinary iodine concentration. Methods Urinary iodine concentrations were determined in the urine samples stored at different durations and under different conditions using new standard method （ammonium persulfate digestion）. Results Relevant deviation （R.D.） of urinary iodine concentration was greater than 10% when testing urine sample was stored at room temperature （RT） and treated by acid from 30 to 60 days, and R.D. values for urine stored otherwise were all less than 10%. Iodine concentrations in acid-treated urine were higher（tRT = - 2.23, t4℃ = - 2.74,P 〈 0.05） than or similar （t = - 1.19,P 〉 0.05） to those in non-treated urine stored at either room temperature, 4 ℃ or - 20 ℃. Storage temperature had no effect on iodine concentrations in non-treated and acidtreated urine（F = 0.051 .F = 0.981 ,P 〉 0.05）. Conclusions Urine samples will be stable for 2 months when stored at room temperature （without acid treatment） and 4 ℃（with and without acid treatment）, and stable at least for 4 months when stored at - 20 ℃ with and without acid treatment.