Preparation and stability of urine arsenic quality control samples / 中华地方病学杂志

ABSTRACT

Objective:To establish a method for preparing urine arsenic quality control samples and verify its uniformity and stability.Methods:Urine samples of healthy adults were collected, concentrated and then freeze-dried using a freeze dryer. The freeze-dried samples were subjected to atomic fluorescence spectrophotometry to determine the arsenic content. The method was verified from the uniformity, stability, determination of different detection methods, and the fixed value of urine arsenic content.Results:The linear correlation coefficient of the standard curve of the method was 0.999 7. The variation coefficients of arsenic content after freeze-dried of urine samples were all < 5%. The uniformity test results showed that there was no statistically significant difference in the arsenic content between bottles of low and high concentration samples ( t = 1.09, 1.53, P > 0.05), and the sample uniformity was good. The stability test results show that the decline rate of the freeze-dried samples of high and low concentrations stored ≤360 days was less than 10%, and the stability was good at room temperature. Atomic fluorescence spectrophotometry and inductively coupled plasma mass spectrometry(ICP-MS) were used for the arsenic content determination of high and low concentration samples, and there was no significant difference between the two methods ( P > 0.05). The results of determination of arsenic content in urine of 14 provinces and 86 cities and counties showed that the low concentration was (0.028 ± 0.002) mg/L and the high concentration was (0.113 ± 0.008) mg/L. Conclusion:The uniformity and stability of the freeze-dried urine arsenic quality control samples can meet the external quality control requirements of the laboratory in endemic disease prevention and monitoring.