2. Experimental
2.1. Chemicals and reagents
Aflatoxin standards and trifluoroacetic acid (TFA) were purchased from Sigma–Aldrich, USA, while acetonitrile, methanol (HPLC grade) and n-hexane were purchased from Fisher Scientific (UK), 18 Mohm milliQ water was generated from a TKA Water Treatment System. Isolute Multimode Columns (1 mL capacity,100 mg), hereafter referred to as multifunctional column (MFC) were purchased from International Sorbent Technology, UK. Forty-two feed samples were obtained from various outlets in Malaysia. Most of these samples, except for copra meal and palm kernel meal, were imported from different countries.