Determination of multi - pesticide residues in coconut water by QuEChERS - dSPE ionic liquid - based DLLME couple with high performance Liquid Chromatography - Tandem Mass Spectrometry (LCMS/MS)

Abstract

The use of pesticides in agricultural practices is very vital but continuously accumulates in water, moist soil and contaminate fruits and vegetables. This eventually leads to many health issues such as congenital diseases and different forms of cancers. For this reason, the validated (SANTE 11831-2017) method of quick, easy, cheap, effective, rugged and safe (QuEChERS) with the dispersive solid phase extraction (SPE) coupled with ionic liquid-based (IL-based) in dispersive liquid-liquid microextraction (DLLME) was used for sample preparation of coconut water to determine multiple pesticides (Dursban, Diazinon, Thiamethoxam, Metalaxyl, Thiobencarb, Baycarb, Carbaryl and Propamocarb) residue using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) instrument. The results of accuracy for relative recoveries (84 - 134%) were satisfactory because 87.5% of results were within the recommended range (70 - 120%). The precision results range (0-19%) of relative standard deviation (RSD) were also satisfactory as recommended (≤ 20%). The resulted limit of detection (LOD) and quantitation (LOQ) was satisfactorily ranged 0.08-0.92 and 0.28-3.08μg/kg respectively. The linearity range results (5 – 500 μg/kg) were evaluated (linear) with regression coefficient (R²) > 0.97. The matrix effects range (≤ -72%) were very weak. The measurement uncertainties range (7 - 27%) estimated were satisfactory as recommended (≤ 50%). Conclusively, the research indicates the reliability of the sample preparation method for multiple pesticides analysis in coconut water. Also, the concentration level for each of the pesticide analysed was found lower than the European Union maximum residue limits, which presumes that the analysed sample is safe for consumption to avoid health-related issues.

Keywords: Dispersive, Liquid-Liquid Microextraction, Solid-Phase Extraction, HPLC-MS, Pesticides, QuEChERS