On-line molecularly imprinted solid-phase extraction for the selective spectrophotometric determination of nicotine in the urine of smokers.
This work describes an on-line molecularly imprinted solid-phase extraction (MISPE) method for spectrophotometric determination of nicotine in urine samples of smokers. This method is based on manganese (VII) to manganese (VI) reduction in an alkaline medium, promoted by nicotine. Two wash solutions (1:4 (v/v) acetonitrile:sodium hydroxide--pH 11.4, and nitric acid--pH 2.5) were employed to circumvent interferences. Aqueous solutions containing nicotine plus different possible concomitants (cotinine, anabasine, norcotinine and caffeine) were tested individually. The analytical calibration curve was prepared in urine samples collected from non-smokers and spiked with nicotine standard from 1.1 to 60 micromol L(-1) (r(2)>0.998). The limit of quantification and the analytical frequency were 1.1 micromol L(-1) and 11 h(-1), respectively. The precision, evaluated using 3, 10 and 30 micromol L(-1) nicotine in urine, was 10, 10 and 4% (intra-day precision) and 12, 13 and 5% (inter-day precision), respectively. Accuracy was checked through high performance liquid chromatography and the results did not present significant differences at the 95% confidence level according to the Student's t-test.
Figueiredo
Eduardo Costa
EC
Group of Spectrometry, Sample Preparation and Mechanization-GEPAM, Institute of Chemistry, P.O. Box 6154, University of Campinas, 13083-970 Campinas, SP, Brazil.
de Oliveira
Daniela Mayra
DM
de Siqueira
Maria Elisa Pereira Bastos
ME
Arruda
Marco Aurélio Zezzi
MA
D002021:Buffers; D002138:Calibration; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009538:Nicotine / Q000652:urine*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012907:Smoking / Q000652:urine*; D013053:Spectrophotometry / Q000379:methods*; D013696:Temperature
D002021:Buffers; D009538:Nicotine