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 3

Effect of extraction solvent volume. Extraction conditions: sample size, 5 mL; extraction solvent, acetonitrile; amount of salt added, 30% NaCl (m/v); pH of solution, 7.0; vortex agitation time, 1 min; centrifugation speed, 4000 rpm for 5 min; n = 6.