Refinement of the use of the NCPC rapid test kits of organophosphate, carbamate and pyrethroid insecticides in grains and fruiting, tuber vegetables

Date

10-1999

Degree

Bachelor of Science in Agricultural Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Susan May F. Calumpang

Abstract

Semi-quantitative color detection limits(color chart schemes) of selected organophosphate, carbamate, and pyrethroid insecticides were developed. Like the other organophosphate insecticides selected tested previously, methamidophos displayed a blue color. The carbamate insecticides exhibited various colors. Carbaryl produced a blue color, carbofuran exhibited a violet color, BPMC displayed a stable pink spot, and methomyl produced a stable pik color. The color produced by the two pyrethroid insecticides, deltamethnrIn and cypermethrin, was violet-brown under ultra-violet radiation. Cyfluthrin, on the other hand, showed no color changes at the insecticide levels tested(0.05 - 1.0ug).

Methamidophos had a minimum detection limit of 0.10 ug, and a maximum quantifiable limit of 0.70 ug. The minimum and maximum detection limits for carbaryl, carbofuran, BPtviC, and methomyt were at 0.05 ug to 0.90 ug, 0.05 ug to 0.60 ug, and 1.0 ug to 10.0 ug, respectively. The minimum and maximum detectable limits were 0.05 ug to 0.70 ug, respectively for both cypermethrin and deltamethrin.

Improvement of the parameters of the Rapid Test Klts(RTK) for pyrethroid insecticides was evaluated. Proper development of the TLC plastic strips was found necessary. It was established that 50mmX 12m m TLC plastic strips were most suitable for the rapid test kits and that two scoops having different dimensions have to be included in the RTK in order: to simplify the method without compromising accuracy.

Methods for the detection of selected pyrethroid, organophosphate, and carbamate insecticides in grains(munghean, corn, and rice(with and without hull)) wee developed. Deltamethrin, cypermethrin could be detected at 2 mg/kg, 0.30 mg/kg, and 8 mg/kg, respectively. Carbaryl in mungbean could be detected at 5 mg/kg. The amounts of residues detected using developed methods for grains conformed with the theoretical values. The methods developed for deltamethrin and cypermethrin could detect residue levels slightly higher than the Codex Maximum Residue Limits(CXL) for deltamethrin and cypermethrin, while those developed for malathion and carbaryl could be easily detect residues equal to or higher than their CXLs in grains. Accuracy of the methods was validated using GC or UV spectrophotometry.

The weight correction factor for fruiting and tuber vegetables was determined. It was found out that without the weight correction factor, a gross over-estimation of residue levels could occur and this may give rise to potential problems in the field.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 1999 A13 M67

Document Type

Thesis

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