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Table 4 Procedure for Spiking and Extraction

From: Pesticides residue analysis in yam from selected markets across Ghana and Belgium: an evaluation of the QUECHERS method

Step Description
1 10 g of blended yam samples were weighed in 50 ml centrifuge tubes on Sartorius analytical balance.
2 Blank samples were spiked with 100 μL of mixed standard of the 25 compounds involved in 8 replicates.
3 15 mL of acetonitrile containing 1% glacial acetic acid (v/v) was added in each sample by using a solvent dispenser.
4 Each tube was tightly cupped and shaken for 1 min to ensure contact between the solvent and the sample matrix.
5 6 g anhydrous MgSO4, 1.5 g NaCL, 1.5 g sodium citrate tribasic dihydrate (C6H2Na3O7 2H2O and 0.75 g sodium hydrogen citrate (C6H6Na2O7 1.5H2O) were added and the sample was shaken for 5 min on a mechanical shaker at 300 rpm to enhance sample throughput.
6 The samples were centrifuged at 10,000 rpm for 5 min.
7 5 mL aliquot of extract was taken into a 10 mL test tube.
8 1 mL of the aliquot of extract in the 10 mL tubes was taken into 10 mL flask and diluted to 10 mL with water.
9 1 mL extract was then transferred from the 10 mL flask into an auto sampler vial for LC-MS/MS analysis.