Simultaneous Preconcentration of Oxyfluorfen and Chlorpyrifos in Environmental Water Samples Using Spent Coffee Grounds as SPE Sorbents

A new procedure for the simultaneous determination of Oxyfluorfen and Chlorpyrifos pesticides in environmental aqueous samples was developed. It was based on solid-phaseextraction (SPE) using spent coffee grounds (a residue from soluble coffee industry and/orcoffee shops) as sorbents and high-performance liquid chromatography-ultraviolet detector forthe enrichment and determination of the two pesticides at trace level. Some parameters thatinfluence the enrichment efficiency of spent coffee grounds towards those pesticides, such aseluent type and its volume, pH of the water sample, volume of the water sample, mass of thesorbent, and column regeneration were investigated and optimized in detail. Under the optimalSPE conditions, the linear range, detection limit, and precision (R.S.D. n=3) were 0.77-50 ngmL^-1, 0.23 ngmL^-1, 4.5-0.1% for Oxyfluorfen; 3.21-100 ngmL^-1, 0.96 ngmL^-1, 1.7-0.3%for Chlorpyrifos, respectively. The proposed method was successfully applied to the analysis of tap water and stream water samples and satisfactory spiked recoveries were obtained in the range of 100.3–106.2 %. The above results indicated that the developed method could be used for the routine analysis in environmental water samples.