Photolysis of phoxim on glass and on tomato leaves

Makary, M. H.; Riskallah, M. R.; HEGAZY, MOHAMED E. A.; Belal, M. H.

doi:10.1007/bf01622112

Cited by 8 publications

(6 citation statements)

References 9 publications

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“…The LOD for phoxim was less than 0.002 mg/kg and LOQ was 0.006 mg/kg, below the MRL of this pesticide in wheat samples which is 0.05 mg/kg. Moreover, the LOD for phoxim in this study was greatly lower than that obtained by TLC (0.1 mg/kg) (Makary and others 1981), lower than that by liquid‐phase microextraction (LPME)‐HPLC‐DAD (0.01 mg/kg) (Liang and others 2005), that from continuous‐flow microextraction (CFME)‐HPLC (0.005 mg/kg) (Guo and others 2005) and that by LC/MS/MS (0.0025 mg/kg) (Hatakeyama and others 2006). Obviously, this improved method of HPLC‐DAD had high sensitivity for determination of phoxim in wheat grain.…”

Section: Resultscontrasting

confidence: 55%

“…It was clear that the presence or absence of light in the extraction of phoxim affected significantly the recovery of the targeted pesticide in wheat grain. The lower recovery of phoxim, if sample extraction was exposed to light, was partly attributed to the property of photolysis on sunlight (Makary and others 1981; http://www.inchem.org/documents/jmpr/jmpmono/v83pr35.htm). It was noted that 3 h were required to extract phoxim contained in wheat samples with PE under darkness while the remaining steps only took about 15 to 20 min in phoxim extraction.…”

Section: Resultsmentioning

confidence: 99%

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Improved Determination of Phoxim Residue in Stored Wheat by HPLC with DAD

Lv¹,

Gao²,

Gao³

et al. 2009

Journal of Food Science

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This article presents an improved method to detect the phoxim residual in whole wheat grain (not milled). The authors used petroleum ether (PE) as solvent to extract phoxim in darkness, and then determined it with high-performance liquid chromatography (HPLC) with diode array detector (DAD) at 280 nm. Use of PE improved the extraction efficiency of phoxim from grain samples over those obtained using acetone, recovery of 83.3% and 65.9%, respectively. Light produced more side effect on the extraction of this pesticide than with darkness, recovery of 63.2% and 83.3%, respectively. The combination of PE with darkness yielded a higher recovery of phoxim in liquid-phase extraction. The peak area of phoxim compared with its absolute values of phoxim in standard solution concentration range from 0.005 mg/kg to 0.253 mg/kg showed a good linear calibration (R(2) = 0.9999). Recoveries, at spiked concentrations of 0.02, 0.05, and 0.10 mg/kg, varied between 83.3% and 106.3% with relative standard deviations (RSD) ranging from 6.5% to 8.0%. The present method provides sufficient sensitivity as reflected by the values of limit of detection (LOD) and limit of quantification (LOQ). LOD was 0.002 mg/kg (S/N 3), and the estimated LOQ was 0.006 mg/kg (S/N = 10). Use of the proposed method successfully detected phoxim residue in wheat grain from Beijing and Kunming City of China.

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Section: Resultscontrasting

confidence: 55%

Section: Resultsmentioning

confidence: 99%

Improved Determination of Phoxim Residue in Stored Wheat by HPLC with DAD

Lv¹,

Gao²,

Gao³

et al. 2009

Journal of Food Science

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show abstract

“…21 However, it is unstable when exposed to light. 22,23 In the current study, phoxim MCs were prepared with two different wall materials (PUA and UF), and their stomach and contact toxicities to the black cutworm, Agrotis ipsilon, were investigated. Ultraviolet irradiation experiments were carried out to examine the effect of UV irradiation on the remaining amounts of phoxim and the contact toxicity of PUA-MCs, UF-MCs, and emulsifiable concentrate (EC).…”

Section: ■ Introductionmentioning

confidence: 99%

Phoxim Microcapsules Prepared with Polyurea and Urea–Formaldehyde Resins Differ in Photostability and Insecticidal Activity

Zhang

et al. 2016

J. Agric. Food Chem.

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The application of pesticide microcapsules (MCs) in agriculture is becoming more and more popular. In this study, the effects of different wall materials on the stomach toxicity, contact toxicity, length of efficacy, and photolysis characteristics of pesticide microcapsules were investigated. The results showed that microencapsulation reduced the stomach and contact toxicities of phoxim and prolonged the efficacy of this light-sensitive chemical in the greenhouse test. Neither of the degradation curves for microencapsulated phoxim under ultraviolet light fit a first-order model, although the emulsifiable concentrate (EC) degradation curve fit it well. The phoxim-loaded polyurea microcapsules (PUA-MCs) showed significantly increased UV-resistance ability, stomach toxicity, and contact toxicity compared with the phoxim-loaded urea-formaldehyde microcapsules (UF-MCs). These experiments indicated that it is crucial to select the appropriate wall materials for pesticide microcapsules on the basis of application sites and physicochemical properties of pesticide active ingredients.

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“…Although the degradation products were not identified, Meikle et al (1983) utilized Whatrnan No. Phoxim (152) gave the same photoproducts on glass and tomato leaf but their chemical identification was not extensively conducted (Makary et al 1981). When the aryl moiety is transformed from simple phenyl rings to heterocycles, similar phototransformation is basically observed.…”

Section: Photodegradation Of Pesticides On Glass and Silica Gel Sumentioning

confidence: 95%

“…For 14C_ cyanophos (137) on bean plants, photolysis was of minor importance (Chiba et al 1976). When phoxim (152) was applied outdoors to tomato plants, the surface rinse of leaves with acetone was found to contain two unknown photoproducts more polar than (152) (Makary et al 1981). In contrast, fenthion (143) was very rapidly degraded on coastal bermudagrass or com plants with successive oxidation of the S-methyl sulfur to form the corresponding sulfoxide and sulfone (Leuch and Bowman 1968).…”

Section: Photodegradation Of Pesticides On Plantsmentioning

confidence: 99%

Reviews of Environmental Contamination and Toxicology

2004

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Photolysis of phoxim on glass and on tomato leaves

Cited by 8 publications

References 9 publications

Improved Determination of Phoxim Residue in Stored Wheat by HPLC with DAD

Improved Determination of Phoxim Residue in Stored Wheat by HPLC with DAD

Phoxim Microcapsules Prepared with Polyurea and Urea–Formaldehyde Resins Differ in Photostability and Insecticidal Activity

Reviews of Environmental Contamination and Toxicology

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