Gm. Shan et al., An enzyme-linked immunosorbent assay for the detection of esfenvalerate metabolites in human urine, CHEM RES T, 12(11), 1999, pp. 1033-1041
The pyrethroids are one of the most heavily used insecticide classes in the
world. Sensitive and rapid analytical techniques are needed for assessment
s of human exposure to these compounds. Highly sensitive and selective ELIS
As for glycine conjugates of esfenvalerate key metabolites phenoxybenzoic a
cid (PBA) and s-fenvalerate acid (sFA) were developed. Rabbits were immuniz
ed with either N-(3-phenoxybenzoyl)-4-amino-L-phenylalanine or N-[(S)-4-chl
oro-2-(methylethyl)benzeneacetyl]-4-amino-L-phenylalanine-fetuin and all se
ra were screened against numerous coating antigens. The antibodies with the
least interference and best sensitivity were optimized and characterized.
The I(50)s for sFA-glycine and PBA-glycine in buffer were found to be 0.40
+/- 0.12 mu g/L (1.47 +/- 0.44 nmol/L) and 0.42 +/- 0.18 mu g/L (1.56 +/- 0
.67 nmol/L), respectively. Both assays exhibited high selectivity. Little o
r no cross reactivity to the parent compound and other metabolites was meas
ured. The matrix effects of urine were investigated. Solid-phase extraction
(SPE) strategies were used in an attempt to decrease the matrix effects an
d increase the sensitivity of the overall method. The limit of quantitation
(LOQ) for both sFA-glycine and PBA-glycine in urine with SPE is 1.0 mu g/L
(3.70 nmol/L). These assays could be used as markers of exposure for monit
oring biological samples.