What are we determining using gas chromatographic multiresidue methods: tralomethrin or deltamethrin?

Valverde, Antonio; Aguilera, Ana M.; Rodríguez, Mariano; Boulaid, Mourad

doi:10.1016/s0021-9673(01)01414-5

Cited by 33 publications

(22 citation statements)

References 7 publications

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“…BIFE and λ‐CYHA presented a base peak at m/z 205 that corresponded to loss of HCl from the carboxyl‐trifluorochlorovinylcyclopropane fragment formed by cleavage of the ester bond. For DELTA and TRALO, it is known that under the GC conditions commonly used in pesticide residue analysis, tralomethrin breaks down to deltamethrin in the injector port of the GC system 21. The mass spectrum of DELTA/TRALO was characterized by the bromide ion base peak at m/z 79 and 81.…”

Section: Resultsmentioning

confidence: 99%

Performance of gas chromatography/tandem mass spectrometry in the analysis of pyrethroid insecticides in environmental and food samples

Feo

Eljarrat

Barceló

2011

Rapid Comm Mass Spectrometry

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The performance of gas chromatography coupled with tandem mass spectrometry (GC/MS/MS) was tested for the simultaneous determination of twelve pyrethroid insecticides. First, a comparison of two different ionization modes, electron ionization (EI) and negative chemical ionization (NCI), was carried out using MS and MS/MS. NCI-MS/MS provided the best results in terms of selectivity and sensitivity giving very low detection limits of 0.11 to 450 fg injected. The reliability of the method was confirmed through the evaluation of quality parameters such as accuracy (70-100%), and repeatability and reproducibility, with coefficients of variation below 15% and 10%, respectively. The applicability of the GC/MS/MS method to real samples and influence of matrix effects were evaluated through the analysis of spiked water, sediment and milk at 0.25 ng L(-1) , 5 ng g(-1) dry weight (dw) and 25 ng g(-1) (dw), respectively, of each pyrethroid insecticide considered. Using GC/NCI-MS/MS, matrix spectral interferences were minimized providing method limits of detection (MLODs) of 0.05-2.59 ng L(-1) , 0.10-87.7 pg g(-1) dw, 2.29-1071 pg g(-1) lipid weight (lw) for water, sediment and milk, respectively. To the best of our knowledge, the MLOD values found in our study were better than those reported in previous studies; in particular for sediment and food samples, they were one order of magnitude lower.

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Section: Resultsmentioning

confidence: 99%

Performance of gas chromatography/tandem mass spectrometry in the analysis of pyrethroid insecticides in environmental and food samples

Feo

Eljarrat

Barceló

2011

Rapid Comm Mass Spectrometry

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“…Loss of bromide ion results in the formation of deltamethrin. A LiChroCART 125-4 Superspher 100 RP-18 column (Hewlett-Packard) was used by Valverde et al (2001) to separate and detect the two diasteroisomers (G and H) of tralomethrin by LC-ES-MS (Table C15, Appendix C).…”

Section: Analytical Methods For Pyrethroid Isomersmentioning

confidence: 99%

Parameters for Pyrethroid Insecticide QSAR and PBPK/PD Models for Human Risk Assessment

Knaak

Dary²,

Zhang

et al. 2012

Reviews of Environmental Contamination and Toxicology

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In this review we have examined the status of parameters required by pyrethroid QSAR-PBPK/PD models for assessing health risks. In lieu of the chemical,biological, biochemical, and toxicological information developed on the pyrethroids since 1968, the finding of suitable parameters for QSAR and PBPK/PD model development was a monumental task. The most useful information obtained came from rat toxicokinetic studies (i.e., absorption, distribution, and excretion), metabolism studies with 14C-cyclopropane- and alcohol-labeled pyrethroids, the use of known chiral isomers in the metabolism studies and their relation to commercial products. In this review we identify the individual chiralisomers that have been used in published studies and the chiral HPLC columns available for separating them. Chiral HPLC columns are necessary for isomer identification and for developing kinetic values (Vm,, and Kin) for pyrethroid hydroxylation. Early investigators synthesized analytical standards for key pyrethroid metabolites, and these were used to confirm the identity of urinary etabolites, by using TLC. These analytical standards no longer exist, and muste resynthesized if further studies on the kinetics of the metabolism of pyrethroids are to be undertaken.In an attempt to circumvent the availability of analytical standards, several CYP450 studies were carried out using the substrate depletion method. This approach does not provide information on the products formed downstream, and may be of limited use in developing human environmental exposure PBPK/PD models that require extensive urinary metabolite data. Hydrolytic standards (i.e., alcohols and acids) were available to investigators who studied the carboxylesterase-catalyzed hydrolysis of several pyrethroid insecticides. The data generated in these studies are suitable for use in developing human exposure PBPK/PD models.Tissue:blood partition coefficients were developed for the parent pyrethroids and their metabolites, by using a published mechanistic model introduced by Poulin and Thiele (2002a; b) and log DpH 7.4 values. The estimated coefficients, especially those of adipose tissue, were too high and had to be corrected by using a procedure in which the proportion of parent or metabolite residues that are unbound to plasma albumin is considered, as described in the GastroPlus model (Simulations Plus, Inc.,Lancaster, CA). The literature suggested that Km values be adjusted by multiplying Km by the substrate (decimal amount) that is unbound to microsomal or CYPprotein. Mirfazaelian et al. (2006) used flow- and diffusion-limited compartments in their deltamethrin model. The addition of permeability areas (PA) having diffusion limits, such as the fat and slowly perfused compartments, enabled the investigators to bring model predictions in line with in vivo data.There appears to be large differences in the manner and rate of absorption of the pyrethroids from the gastrointestinal tract, implying that GI advanced compartmental transit models (ACAT) need to be included in PBPK mo...

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“…In addition, the GC methods will detect either the parent compound or the 3-phenoxybenzoic acid and Br 2 CA metabolites, but not both. A recent paper by Valverde et al has pointed out an additional concern for the use of gas chromatography for the determination of deltamethrin [18]. This paper shows that the pyrethroid pesticide tralomethrin is thermally degraded to deltamethrin in the injection port of a gas chromatograph leading to concerns about the ability of GC methods to accurately quantitate deltamethrin in the presence of tralomethrin.…”

Section: Introductionmentioning

confidence: 99%

Determination of deltamethrin and its metabolite 3-phenoxybenzoic acid in male rat plasma by high-performance liquid chromatography

Ding¹,

White²,

Muralidhara³

et al. 2004

Journal of Chromatography B

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What are we determining using gas chromatographic multiresidue methods: tralomethrin or deltamethrin?

Cited by 33 publications

References 7 publications

Performance of gas chromatography/tandem mass spectrometry in the analysis of pyrethroid insecticides in environmental and food samples

Performance of gas chromatography/tandem mass spectrometry in the analysis of pyrethroid insecticides in environmental and food samples

Parameters for Pyrethroid Insecticide QSAR and PBPK/PD Models for Human Risk Assessment

Determination of deltamethrin and its metabolite 3-phenoxybenzoic acid in male rat plasma by high-performance liquid chromatography

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