Ochratoxin A quantification: Newly developed HPLC conditions

Ochratoxin A (OTA) is a mycotoxin that has been classified as a Group 2B carcinogen, which means that it belongs to a group of possible carcinogens to humans. The main objective of the present study was to optimize the High Performance Liquid Chromatography (HPLC) parameters including pH (X1), temperature (X2) and flow rate (X3) for quantitative analysis of OTA (Y4) in spiked peanuts. Significant nonlinear response surface model with high coefficient of determinations (R2) was fitted to evaluate the effect of HPLC parameters on the quantification level of OTA. All HPLC variables had significant (p < 0.05) effect on the quantification level of OTA. The highest quantification value for OTA was obtained with the following HPLC conditions: mobile phase consisting of 5 mM sodium acetate (acidified to pH 2.36 with acetic acid)/ACN/MeOH (40:30:30); excitation of 333 nm; emission of 467 nm; flow rate of 0.4 mL/min; and temperature of 24 °C. The recommended optimal HPLC conditions provided a 2.2-fold and 4.7-fold higher peak area for OTA when compared to the other two conditions. The recovery and LOD values of OTA under the recommended optimal conditions were 95.4% and 0.05 ng/g, respectively. The OTA contents of six different raw peanut brands were quantified using the newly optimized HPLC conditions, and the results demonstrated that all six brands were contaminated with OTA, with concentrations ranging from 2.82 to 7.41 ng/g.