Monitoring of Total Type II Pyrethroid Pesticides in Citrus Oils and Water by Converting to a Common Product 3-Phenoxybenzoic Acid

Abstract

Pyrethroids are a class of insecticides that are becoming increasingly popular in agricultural and home use applications. Sensitive assays for pyrethroid insecticides in complex matrices are difficult with both instrumental and immunochemical methods. Environmental analysis of the pyrethroids by immunoassay requires either knowing which pyrethroids contaminate the source or the use of nonspecific antibodies with cross-reactivities to a class of compounds. We describe an alternative method that converts the type II pyrethroids to a common chemical product, 3-phenoxybenzoic acid (3-PBA), prior to analysis. This method is much more sensitive than detecting the parent compound, and it is much easier to detect a single compound rather than an entire class of compounds. This is useful in screening for pyrethroids as a class or in situations where a single type of pyrethroid is used. We demonstrated this technique in both citrus oils and environmental water samples with conversion rates of the pyrethroid to 3-PBA that range from 45 to 75% and methods that require no extraction steps for either the immunoassay or the liquid chromatography−tandem mass spectrometry (LC-MS/MS) techniques. Limits of detection for this technique applied to orange oil are 5 nM, 2 μM, and 0.8 μM when detected by LC-MS/MS, gas chromatography−mass spectrometry, and immunoassay, respectively. The limit of detection for pyrethroids in water when detected by immunoassay was 2 nM.

Simultaneous Degradation of Cypermethrin and Its Metabolite, 3-Phenoxybenzoic Acid, by the Cooperation of Bacillus licheniformis B-1 and Sphingomonas sp. SC-1

“…These might be because cyano-3-phenoxybenzyl alcohol was gradually oxidized to 3-phenoxybenzaldehyde and then to 3-PBA. 12 At 72 h, CY degradation and 3-PBA content reached 50.36% and 23.16 mg L −1 , respectively. Compared with other CY-degrading organisms, such as Pseudomonas IES-Ps-1 isolated by Jilani and Khan that could degrade 51% CY (80 mg L −1 ) in 48 h 22 and Bacillus sp.…”

“…In the initial cultivation phase (0−24 h), the OD 600 value and CY degradation all exhibited rapid increase trends, and the CY degradation reached 23.35% at 24 h, whereas only 0.72 mg L −1 3-PBA was detected. This might be due to the fact that CY was first degraded into cyano-3-phenoxybenzyl alcohol by esterase produced by strain B-1, 12 and only a very small amount of cyano-3-phenoxybenzyl alcohol was transformed to 3-PBA. From 24 to 72 h, the CY degradation continued to increase, and the 3-PBA content began to increase quickly.…”

Co-Metabolic Degradation of β-Cypermethrin and 3-Phenoxybenzoic Acid by Co-Culture of Bacillus licheniformis B-1 and Aspergillus oryzae M-4

“…Beta-cypermethrin (β-CY) is an important pyrethroid pesticide, its residue can accumulate in the human body through the food supply chain and exhibit toxic effects on the human reproductive, immune, and nervous systems [4–6]. As a β-CY metabolite, 3-phenoxybenzoic acid (3-PBA) is difficult to degrade further in the environment due to its diphenyl oxide structure [7]. Heudorf et al [8] reported that 3-PBA residue in urine of children and adolescents in Germany was 0.30 μg/L.…”

Screening methodologies for the determination of water contaminant residues by compact disk technology

“…Recently, McCoy at al. 204 have developed a method based on HPLC/MS with an electrospray interface (ESI) to detect type II pyrethroids by converting them to 3-PBA. Also, GC-ECD was successfully employed for 3-PBA detection in water samples.…”

“…205 Alternative low-cost bioanalytical approaches have been reported. Traditional ELISA tests 204,206,207 for different matrices as well as fluorescence immunoassay have been developed. …”