title: Superiority of nitric acid for deproteinization in the determination of trace lithium in serum by graphite furnace atomic absorption spectrometry.
abstract: Physiological level of trace lithium in human serum was determined by graphite furnace atomic absorption spectrometry (GFAAS). 3.5% HNO3 (v/v) was employed as a protein precipitant for sample treatment and at the same time verified as a very effective chemical modifier to eliminate the interference of chloride. The analytical conditions for lithium determination in serum were investigated and the optimal pyrolysis and atomization temperatures were 800 degrees C and 2700 degrees C. The accuracy and precision of the method were tested by determining lithium in a RANDOX HN1530 assayed human multi-sera and a pooled human serum. The result was in good agreement with the target value and CV of the pooled human serum was 4.74% (n=10). The characteristic mass, the limit of detection (LOD) of the proposed method were 0.8 pg and 0.01 micromol/L, respectively. Median+/-S.E.M. of serum lithium in 220 Chinese people was 0.25+/-0.02 micromol/L.
authors.affiliation: Shanghai Key Laboratory of Vascular Biology at Ruijin Hospital and Shanghai Institute of Hypertension, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai 200025, China. jzhao021@yahoo.com
authors.forename: Jianxing
authors.initials: J
authors.lastname: Zhao
authors.forename: Pingjin
authors.initials: P
authors.lastname: Gao
authors.forename: Shengnan
authors.initials: S
authors.lastname: Wu
authors.forename: Dingliang
authors.initials: D
authors.lastname: Zhu
mesh_terms: D001774:Blood Chemical Analysis; D002138:Calibration; D002623:Chemistry Techniques, Analytical; D002681:China; D005260:Female; D006108:Graphite / Q000737:chemistry; D006801:Humans; D008094:Lithium / Q000032:analysis* / Q000097:blood*; D008297:Male; D017942:Nitric Acid / Q000737:chemistry* / Q000494:pharmacology; D012016:Reference Values; D015203:Reproducibility of Results; D012965:Sodium Chloride / Q000737:chemistry; D013054:Spectrophotometry, Atomic / Q000379:methods*; D013696:Temperature
chemical_list: D017942:Nitric Acid; D012965:Sodium Chloride; D006108:Graphite; D008094:Lithium