To establish a rapid and efficient method for the determination of 12 kinds of organophosphate esters (OPEs) in meat products by cold-induced pretreatment combined with high performance liquid chromatography-tandem mass spectrometry.

Freeze-dried meat samples were extracted with acetonitrile and then purified using C₁₈ and N-propylethylenediamine (PSA) adsorbents; further, the acetonitrile/water ratio of the solution was adjusted to 35:65 (V:V) and then the solution was frozen in a −20 ℃refrigerator to separate and enrich OPEs. The target compounds were quantified using high performance liquid chromatography-tandem mass spectrometry coupled with stable isotope internal standards. The cold-induced procedure was optimized and the linear relation, limits of detection, recovery, precision and matrix effect of the method were validated.

Standard solutions exhibited excellent linearity across 0.1–100.0 ng/mL. The correlation coefficients (r) were all greater than or equal to 0.9993. For the tested 12 kinds of OPEs, the average recovery rates at spiking levels of 1 ng/g and 5 ng/g ranged from 82.6% to 115.9%, with relative standard deviations of lower than or equal to 15.9%. The limits of detection for OPEs ranged from 0.1 to 19.2 pg/g, while the limits of quantitation ranged from 0.2 to 64.0 pg/g. The established method was used for the measurement of fresh and pre-cooked meats and OPEs were ubiquitous in the tested real samples. Moreover, the contamination levels of OPEs in pre-cooked foods were much higher than that in fresh foods.

The established analytical method is simple, rapid and highly sensitive; and only a small quantity of reagents and consumables is needed, making it suitable for monitoring large-scale food samples.