GC/EI-MS and UV-Vis analysis of pesticide residues in cultivated Catha edulis Forsk (Khat) from selected farms in Meru County, Kenya

In this study, an analysis of pesticide residues was performed using a gas chromatography/ electron impact mass spectrometer (GC/EI-MS) to qualitatively assess and characterize in khat leaves sampled from selected agricultural farms Meru County, Kenya. A solid-phase microextraction (SPME) procedure followed by GC/EI-MS led the detection identification six compounds sample-ion chromatograms. They include cypermethrin, acephate, cyhalothrin, cyfluthrin, chlorpyrifos, chlorfenvinphos. The prevalence rate contamination determined be 54.5% sample size. Of identified residues, 50% were based on pyrethroids other organophosphate. Four pesticides chlorinated compounds. quick, easy, cheap, effective, rugged, safe UV-vis double beam spectrophotometric technique copper (II) chelation reactions leading colored complexes developed, validated, applied quantify compare levels found samples. wavelength-scan measurements chelated with ions revealed maximum absorption Cu-cypermethrin Cu-acephate at 321 207 nm, respectively. standards calibration curves developed UV-Vis quantitation showed excellent linearity concentration range 0.5-10.0 µg/L (R2 = 0.99) for both cypermethrin acephate standards. estimated limits quantification (LOQ) 0.25-0.26 µg/L, results samples (in which confirmed present) that (an organophosphate residue) occurred higher (range 2.897-7.978 µg/L) than (2.145 µg/L). For quantitatively analysed samples, below residue limit (MRL). hazard quotients (HQ) between 0.247-0.797.