Solid phase extraction based microfluidic chip coupled with mass spectrometry for rapid determination of aflatoxins in peanut oil

• The pretreatment of sample was completely integrated into the chip. • Microfluidic chip can reduce the usage of reagent and detection time. • This online MS method could detect four aflatoxins accurately. A rapid and automated system for determination of aflatoxins (aflatoxins B1, B2, G1, G2) in peanut oil was developed. This system consisted of solid phase extraction based microfluidic chip and mass spectrometry (SPE-Chip-MS). Aflatoxins were enriched on SPE channel on the microfluidic chip which filled with HP C18 particles, then, they were eluted and introduced into the MS for qualitative and quantitative analysis at multiple reaction monitoring (MRM) mode. Electrospray ionization in the positive ion mode were used for detection of aflatoxins. Using the SPE-Chip-MS system, a series of good linear calibration curves were obtained with the linear range between 1.25 ng/mL and 100 ng/mL, and the detection limits (S/N = 3) of aflatoxins were 0.013–0.067 ng/mL. In this work, the pretreatment of sample was completely integrated into microfluidic chip for the first time and the online MS detection was achieved, and this system could be extended to the detection of various food samples.