Enzymatic-spectrophotometric determination of paraquat in urine samples: a method based on its toxic mechanism.
Paraquat is a broad-spectrum contact herbicide that has been encountered worldwide in several cases of accidental, homicidal, and suicidal poisonings. The pulmonary toxicity of this compound is related to the depletion of NADPH in the pneumocytes, which is continuously consumed by the reduction/oxidation of paraquat and reductase enzyme systems in the presence of O(2) (redox cycling). Based on this mechanism, an enzymatic-spectrophotometric method was developed for the determination of paraquat in urine samples. The velocity of NADPH consumption was monitored at 340 nm, every 10 s during 15 min. The velocity of NADPH oxidation correlated with the paraquat levels found in samples. The enzymatic-spectrophotometric method showed to be sensitive, making possible the detection of paraquat in urine samples at concentrations as low as 0.05 mg/L.
Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Brasil. rafaelmenck@usp.br
Rafael Menck
RM
de Almeida
Mauricio
M
Yonamine
D006540:Herbicides / Q000737:chemistry / Q000506:poisoning / Q000652:urine; D006801:Humans; D008297:Male; D015394:Molecular Structure; D009249:NADP / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D010269:Paraquat / Q000737:chemistry / Q000506:poisoning / Q000652:urine; D013053:Spectrophotometry / Q000379:methods*; D055815:Young Adult
D006540:Herbicides; D009249:NADP; D010269:Paraquat