Miller N L, Durr J A, Alfrey A C
Department of Medicine, University of Colorado School of Medicine, Denver.
Anal Biochem. 1989 Nov 1;182(2):245-9. doi: 10.1016/0003-2697(89)90587-3.
A highly sensitive flameless atomic absorption method has been adapted for the determination of endogenous trace lithium levels in serum and urine. With ammonium nitrate as the only matrix modifier, serum levels of Li as low as 0.03 mumol/liter are measured accurately and there is no requirement for standard additions. The need for background correction during analysis was clearly established, and tungsten and Zeeman-effect background corrections were compared. The tungsten correction offered superior sensitivity and linearity of standards. Recoveries in urine and serum average 94.8 +/- 7.7 and 95.3 +/- 6.1% (+/- SD), respectively. The endogenous serum Li levels were 0.16 +/- 0.08 mumol/liter for normal subjects dwelling in the Denver metropolitan area. The mean 24-h excretion rate was 5.24 +/- 1.4 mumol/day. The mean fractional excretion of endogenous Li (clearance Li/clearance creatinine) was 23.2 +/- 3.0%, a value similar to values published for exogenously administered Li and measured by conventional methods.
一种高灵敏度无火焰原子吸收法已被用于测定血清和尿液中的内源性痕量锂水平。以硝酸铵作为唯一的基体改进剂，能够准确测定低至0.03微摩尔/升的血清锂水平，且无需标准加入法。明确确定了分析过程中背景校正的必要性，并比较了钨和塞曼效应背景校正。钨校正提供了更高的灵敏度和标准曲线线性。尿液和血清中的回收率分别平均为94.8±7.7%和95.3±6.1%（±标准差）。居住在丹佛市区的正常受试者内源性血清锂水平为0.16±0.08微摩尔/升。平均24小时排泄率为5.24±1.4微摩尔/天。内源性锂的平均排泄分数（锂清除率/肌酐清除率）为23.2±3.0%，该值与通过传统方法测量的外源性给予锂的值相似。
