An LC–MS/MS method for multi-mycotoxin quantification in cow milk

Abstract

The simultaneous quantification of 15 mycotoxins in cow milk by liquid chromatography-mass spectrometry, is presented. Extraction was performed with acidified acetonitrile, followed by a cleanup step with sodium acetate. During validation limits of detection (LOD) and quantification, linearity, precision, accuracy, recovery, matrix effect, and stability were studied. LOD values were between 0.02 and 10.14ng/mL for aflatoxins M1, B1, B2, G1, G2, ochratoxins A and B, HT-2 and T-2 toxins, deepoxy-deoxynivalenol, zearalenone, sterigmatocystin and fumonisins B1, B2 and B3. Recovery values were between 82.6 and 94.4% for all the mycotoxins, except for fumonisins. The recovery values for fumonisins were between 42.1% and 64.6%. Matrix effect, between 25.5 and 96.8%, appeared for all of the mycotoxins, especially for deepoxy-deoxynivalenol, zearalenone and sterigmatocystin. The validated method achieves the quantification of those mycotoxins of major concern and mycotoxins that are not frequently studied in milk, such as fumonisins, sterigmatocystin or ochratoxin B.

Analysis of Mycotoxins in Peruvian Evaporated Cow Milk

“…Recovery and matrix effect for mycotoxins group B were studied at LOQ, 5 × LOQ and 10 × LOQ concentration levels (three independent samples for each concentration level) in one day (within-run), following the methodology described in our previous work [18].…”

“…The same procedure was carried out in order to assure the adequate preparation of stock solutions 2 and 3. Stock solutions 1 and 2 were stored at −20 • C. Mycotoxin stability was previously determined in these same conditions [18,19]. Fumonisins were unstable in acetonitrile and therefore, stock solution 3 was prepared before use.…”

“…Mycotoxin group A was eluted using a gradient program starting with 5% of B solution, in accordance with work carried out by Flores-Flores and González-Peñas [19], and the injection volume was 15 µL. Mycotoxins group B was analyzed in a different run, using a gradient program starting at 40% of B solution, in accordance with work carried out by Flores-Flores and González-Peñas [18], and the injection volume was 20 µL. In both cases, the chromatographic separation was carried out with gradient conditions, although with differences in terms of the rate for increasing the organic phase (B) percentage.…”

“…Data was collected by means of selected reaction monitoring (SRM). The MS parameters for identifying each mycotoxin were those previously used by our group [18,19].…”

“…Each aliquot was used for analyzing a group of mycotoxins (A or B). The extraction procedures were those previously reported by Flores-Flores and González-Peñas [18,19]. In both cases, the extraction was performed with ACN acidified with HCOOH.…”