氘灯校正石墨炉原子吸收测定尿锰方法探讨

目的优化氘灯校正石墨炉原子吸收分光光度法法测定尿锰的条件。方法直接进稀释尿样(1+5)于石墨炉中,分别用硝酸镁、氯化钯、磷酸二氢铵、氯化钯-抗坏血酸、氯化钯+TritonX-100等基体改进剂,优化仪器及试验条件,氘灯校正测定吸光度,工作曲线法定量。结果使用硝酸镁(1.5g/L)作为基体改进剂,与氯化钯、磷酸二氢铵、氯化钯-抗坏血酸、氯化钯-TritonX-100相比,有相对较高的吸光度/背景吸收比、较小的吸收半峰宽、较高的灰化温度、较低的原子化温度。硝酸镁(1.5g/L)用量为8μL～15μL,背景信号基本恒定,灰化温度小于1300℃、原子化温度大于1700℃。线性范围0～20μg/L,直线回归相关系数为0.9995;检出限为0.48μg/L;相对标准偏差为3.12%(10μg/L,11次);加标回收率为97.3%～107.0%。结论氘灯校正石墨炉原子吸收法测定尿锰时,使用硝酸镁作为基体改进剂,效果较理想,能满足检测的需要。

Determination of Manganese in Urine by Graphite Furnace Atomic Absorption Spectrometry With Deuterium Lamp Background Correction

Objective To optimize the conditions for determination of manganese in urine by graphite furnace atomic absorption spectrometry with deuterium lamp correction. Methods With the dilute urine sample （1＋5） directly injected into the graphite furnace,different matrix modifiers including magnesium nitrate,palladium chloride,ammonium dihydrogen phosphate,palladium chloride-antiscorbic acid,palladium chloride-Triton X-100,etc. were tested for optimization of the instrumental and experimental conditions. The absorbance was measured with deuterium lamp correction and manganese in the sample was quantified by working curve method. Results Higher absorbance-background absorption ratio,narrower absorption peak width at half height,higher incineration temperature and lower atomization temperature were produced with magnesium nitrate（1.5 g/L） as the matrix modifier than with palladium chloride,ammonium dihydrogen phosphate,palladium chloride-antiscorbic acid or palladium chloride-Triton X-100. When the amount of magnesium nitrate （1.5 g/L） used was 8μL-15 μL,background signals were basically constant; the incineration temperature was below 1 300 ℃; and the atomization temperature was above 1 700 ℃. The linearity range was 0-20 μg/L. The correlation coefficient was 0.9995. The limit of detection was 0.48 μg/L. The relative standard deviation was 3.12% （10 μg/L,n=11）. The recovery of spiked samples ranged from 97.3% to 107.0%. Conclusion Magnesium nitrate used as the matrix modifier in determination of manganese in urine by graphite furnace atomic absorption with deuterium lamp correction can produce ideal effect and satisfy the detection requirement.