Research Article

A Highly Selective Analytical Method Based on Salt-Assisted Liquid-Liquid Extraction for Trace-Level Enrichment of Multiclass Pesticide Residues in Cow Milk for Quantitative Liquid Chromatographic Analysis

Figure 6

Effect of pH. Extraction conditions: sample size, 5 mL; extraction solvent, acetonitrile; extraction solvent volume, 1000 μL; salt type, MgSO4; amount of MgSO4 added, 40% (m/v); vortex agitation time, 1 min; centrifugation speed, 4000 rpm for 5 min; n = 6.