Authors:
Kenyanya Teresa Mogoi
, Wilkister Nyaora Moturi
, Jane Nyaanga
, Joseph Kinyoro Macharia
and Rhoda and
Jerop Birech ,Kenya
|
Abstract:
Pesticides are used to protect crops from diseases and pests. They have been used in growing
vegetables especially exotic vegetables that are more prone to pests and diseases. There have
been concerns over indiscriminate use of pesticides by farmers to grow vegetables especially for
local markets since there are no guidelines on Maximum residue levels. This study was done to
determine the concentration of cypermethrin and lambda-cyhalothrin pesticide residues in
Collard (Brassica oleracea var. acephala) Tomatoes (Solanum lycopersicum) and swiss chard
(Beta vulgaris subsp. cicla). The samples included both organic and conventional vegetables that
use chemical pesticides. Experimental study design was used which involved laboratory analysis
of the samples. Sample extraction was done using AOAC official method 2007.01 known as
Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method. The method involves use
of Acetonitrile, sodium chloride and anhydrous magnesium sulphate for extraction. Clean-up
was done using dispersive-solid phase extraction method using Primary-Secondary Amine and
anhydrous magnesium sulphate. Residues analysis was done using Reverse-phase High
Performance Liquid chromatography. Peak areas of the curves were calculated using Motic
Images plus 2.0 and data analysis was done using SPSS 22. The results indicated that organic
vegetable samples had pesticide residues below detectable levels while conventional vegetable
samples had levels ranging from 2.495mg/kg to 0.238mg/kg for cypermethrin and 0.352mg/kg to
0.119mg/kg for lambda-cyhalothrin |
