Simultaneous Quantification of Aflatoxin B1, T-2 Toxin, Ochratoxin A and Deoxynivalenol in Dried Seafood Products by LC-MS/MS

Abstract

Mycotoxins are secondary metabolites produced by fungi. These contaminate dried seafoods during processing and storage and represent a potential health hazard for consumers. A sensitive, selective and accurate liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was established for simultaneous quantification of four common mycotoxins (aflatoxin B₁ (AFB₁), T-2 toxin (T-2), ochratoxin A (OTA) and deoxynivalenol (DON)) in dried shrimp, dried fish and dried mussel products. Mycotoxins were extracted from dried seafood samples by acetonitrile/water (85/15, v/v), subjected to ultrasound for 60 min at 20 °C and cleaned up by defatting with n-hexane. The sample matrix affected the linearity of detection (R² ≥ 0.9974). The limit of detection (LOD) and limit of quantification (LOQ) in dried seafood products varied from 0.1 to 2.0 µg·kg^-1 and 0.3 to 5.0 µg·kg^-1, respectively. The method was validated by spiking samples with specific mycotoxin levels, and the recoveries, intra-relative standard deviation (RSDs) and inter-RSDs ranged between 72.2-98.4%, 2.8-10.6%, and 5.5-15.4%, respectively. This method was used to analyze 40 dried seafood products purchased from the Zhanjiang seafood market. Results of this product sampling showed that while no DON was detected, AFB₁, T-2 and OTA were detected in 30.8%, 17.5% and 33.3% of the samples, respectively. AFB₁, T-2 and OTA concentrations varied at 0.58-0.89, 0.55-1.34 and 0.36-1.51 µg·kg^-1, respectively. Relatively high frequency of contamination and the presence of AFB₁, OTA and T-2 residues indicate the need to monitor mycotoxins in dried seafood products.

Keywords: dried seafood; liquid chromatography-tandem mass spectrometry; method validation; mycotoxins; ultrasound-assisted extraction.

Figure 1

LC-MS/MS chromatograms of the four mycotoxins: (A) aflatoxin B₁ (AFB₁), (B) T-2 toxin, (C) ochratoxin A (OTA), and (D) deoxynivalenol (DON) in dried seafood products spiked with 1 mg·L⁻¹ of each of the standards.

Figure 2

Recovery efficiency of (A) different extraction solvents, (B) ratio of extraction solvents, (C) extraction temperature, (D) extraction time, (E) extraction pH, and (F) clean-up columns for aflatoxin B₁ (AFB₁), T-2 toxin (T-2), ochratoxin A (OTA) and deoxynivalenol (DON) in three types of dried seafood product spiked with a 20 μg·L⁻¹ mixture of the mycotoxin standards (n = 5).