Development and application of a method for analysis of lufenuron in wheat flour by gas chromatography-mass spectrometry and confirmation of bio-efficacy against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae).
A new analytical method using gas chromatography with mass spectrometry (GC-MS) for the quantitative determination of lufenuron, a benzoylphenylurea (BPU) class of insecticide, from wheat flour has been developed and applied for time-dependent residue monitoring in treated wheat flour. The analyte was extracted from wheat flour by a single step solid-liquid extraction by using ethyl acetate and subsequently cleaned up using the Primary Secondary Amine as a sorbent prior to GC-MS analysis. The present method provides sufficient sensitivity as reflected by the values of limit of detection (LOD) and limit of quantification (LOQ), 5 ng/mL (S/N approximately 3) and 50 ng/mL (the lowest validation point on the calibration curve), respectively. The calibration curve showed an excellent linearity in the concentration range of 50-1000 ng/mL (r2=0.998). The average recovery for spiked samples at three concentrations (150, 300, and 450 ng/g) was 98.23+/-2.52% R.S.D. The method was applied for the determination of lufenuron residues in treated wheat flour samples. Simultaneous determination of bio-efficacy of lufenuron residues was also carried out against the red flour beetle, Tribolium castaneum to correlate the actual residual effect of lufenuron as detected by the analytical method, over a period of 3 months. The findings revealed that the residual concentration of lufenuron were neither uniform nor in descending order over a period of 3 months in wheat flour, possibly because of an uneven dispersal in the treated wheat which was subsequently milled into flour, as confirmed by GC-MS analysis. However, the residues of lufenuron were sufficient to produce 100% mortality of T. castaneum larvae up to 3 months. The results have been discussed in view of the potential of lufenuron as a candidate molecule for the control of stored product pests.
Ahire
Kedar C
KC
Department of Microbiology, University of Pune, Pune 411007, India.
Arora
Manjit S
MS
Mukherjee
Samindra N
SN
D000818:Animals; D001549:Benzamides / Q000032:analysis* / Q000737:chemistry / Q000494:pharmacology*; D005433:Flour / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007306:Insecticides / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D015394:Molecular Structure; D015203:Reproducibility of Results; D014231:Tribolium / Q000254:growth & development*; D014908:Triticum / Q000737:chemistry*; D005466:Fluorocarbons
D001549:Benzamides; D007306:Insecticides; C070364:fluphenacur; D005466:Fluorocarbons