Flow injection chemiluminescence determination of L-cysteine in amino acid mixture and human urine with the BrO3--quinine system.
In this paper, a novel flow injection chemiluminescence (CL) determination of L-cysteine is proposed. The method is based on the CL reaction of L-cysteine and KBrO3 in acidic medium. The CL intensity was greatly enhanced in the presence of quinine. The CL intensity was linear with L-cysteine concentration in the range of 0.2-80 microg L(-1), and the detection limit was 0.1 microg L(-1) (3 sigma). A complete analysis, including sampling and injecting, could be performed in 1 min, giving a throughput of about 60 h(-1). The relative standard deviation was 1.6% for 0.8 microg L(-1 ) L-cysteine ( n=11). The proposed method was satisfactorily applied to the determination of cysteine in an amino acid mixture and human urine. The mechanism of the CL reaction is also discussed.
Li
Baoxin
B
Department of Chemistry, School of Chemistry and Materials Sciences, Shaanxi Normal University, 710062, Xi'an, P.R. China.
Zhang
Zhujun
Z
Liu
Meilin
M
Xu
Chunli
C
D000596:Amino Acids / Q000737:chemistry*; D001959:Bromates / Q000737:chemistry*; D003545:Cysteine / Q000032:analysis* / Q000652:urine; D017022:Flow Injection Analysis / Q000379:methods*; D006801:Humans; D008163:Luminescent Measurements; D011803:Quinine / Q000737:chemistry*
D000596:Amino Acids; D001959:Bromates; D011803:Quinine; D003545:Cysteine