Alachlor Research Articles

Determination of alachlor and its metabolites in rat plasma and urine by liquid chromatography–electrospray ionization mass spectrometry

A method based on liquid chromatography (LC) in combination with mass spectrometry (MS) for the analysis of alachlor (ALA) and its metabolites, 2-chloro- N-[2,6-diethylphenyl]acetamide (CDEPA) and 2,6-diethylaniline (DEA), in rat plasma and urine has been developed. 13C-labeled ALA was used as the internal standard for quantitation. The analyte in plasma or urine was isolated using a Waters Oasis HLB extraction plate. The mass spectrometer was operated in the ESI MS-SIM mode with a programming procedure. The retention times for ALA, CDEPA and DEA were 1.84, 3.11 and 4.12 min, respectively. The limits of quantification (LOQ) for ALA, CDEPA and DEA were 2.3, 0.8 and 0.8 ng per injection, respectively. The linear fit of analyte to mass response had an R 2 of 0.99. Reproducibility of the sample handling and LC–MS analysis had a RSD of ≤10%. The average recoveries for these analytes in rat plasma were better than 90%. Similar results were obtained with rat urine.

Sepiolite-based materials for the photo- and thermal-stabilization of pesticides

The present work is related to the use of sepiolite for the stabilization of certain photo or thermolabile herbicides by their adsorption on sepiolite-modified materials that act as organo-inorganic supports of the pesticides. The study demonstrates that formulations based on sepiolite containing a cationic dye (thioflavine-T (TFT)) are very effective in the stabilization of a photolabile herbicide (trifluralin (TF)). A modification of the hydrophilic character of the sepiolite surface by adsorption of cationic surfactants enhances the adsorption on the mineral substrate of non-polar pesticides, such as the herbicides alachlor (ACH) or metolachlor (MCH), thus contributing to the decrease of their losses by volatilization.

Development and validation of an ELISA for metolachlor mercapturate in urine

The National Institute for Occupational Safety and Health (NIOSH) has conducted an exposure assessment study of herbicide applicators exposed to numerous commercial acetanilide-containing products. An enzyme-linked immunosorbant assay (ELISA) was developed to measure the putative major human metabolite of one of these, metolachlor mercapturate (MM). Antibodies were obtained by immunizing rabbits with a keyhole limpet hemocyanin (KLH) MM conjugate and the sera used as a source of IgG antibodies for the ELISA development. The percent cross-reactivities for metolachlor (ME), acetochlor mercapturate (ACM), alachlor mercapturate (AM) and alachlor (AL) were 39 and 23, respectively. Cross-reactivity for alachlor mercapturate (AM) and alachlor (AL) are not given as 50% inhibition was not observed for the highest concentration tested. Percent inhibitions at 20 μg l −1 for MM, ME, ACM, AM and AL were 20, 29, 48, 72 and 90, respectively. The measured least detectable dose (LDD) of metolachlor mercapturate was 0.18 μg l −1. Inter-assay concordance was <15%. These data indicate that the MM ELISA developed in this study may be used to estimate body burdens of ME from urinary metabolites of herbicide applicators.

Biochemical and toxicological studies on the mixtures of three commonly-used herbicides in mice

Herbicidal-mixtures have not been adequately studied in biological systems. Therefore, mixtures of three commonly-used herbicides were evaluated. Alachlor (AL), atrazine (AT), picloram (PI), AL+AT, AT+PI, PI+AL and AL+AT+PI, at 10 ppm (in drinking water) of each herbicide, were provided to mice for 30, as well as for 90, days ad libitum; these herbicides and mixtures, at 100 mg/kg (in corn oil) of each herbicide, were also given to additional groups of mice by oral intubation daily for 21 days. In the 30-day test, the spleen/body weight ratios on Day 31 with respect to the control were increased in the AT (53%) and AL+AT (44%) groups. Decreases in the body weights were noted in the treated groups after Day 31 during the 90-day test. Serum glutamic-pyruvic transaminase (SGPT), glutamic-oxalacetic transaminase (SGOT) and alkaline phosphatase activities with AL+AT+PI were elevated by 36-92% on Day 91; SGPT (34%) and SGOT (73%) activities were increased with AL. During the 21-day oral intubation study, the mouse body weights in the mixture groups were generally lower than the control (p < or = 0.05). The liver/body weight ratios were elevated in all groups (16-38%); the spleen/body weight ratio increased with PI (50%). The kidney/body weight ratios were high with PI+AL and AL+AT+PI (p < or = 0.05). Excluding AT, the pentobarbital-induced sleep was less (51-77%) in the herbicide-treated groups. Also, necrosis of individual and small groups of hepatocytes was noted with the mixtures.(ABSTRACT TRUNCATED AT 250 WORDS)

Alachlor and its analogs as metabolic progenitors of formaldehyde: fate of N-methoxymethyl and other N-alkoxyalkyl substituents

Alachlor and its analogs as metabolic progenitors of formaldehyde: fate of N-methoxymethyl and other N-alkoxyalkyl substituents