Detection of trace formaldehyde in beef tripe using doping-assisted positive photoionization high-field asymmetric waveform ion mobility spectrometry.

The illegal addition of formaldehyde during the soaking process of beef tripe poses a serious threat to human health. This paper proposes a method for detecting formaldehyde in beef tripe using dopant-assisted atmospheric pressure photoionization combined with high-field asymmetric waveform ion mobility spectrometry (FAIMS). This technique enables rapid and sensitive detection of formaldehyde. The study investigated the effects of different dopants, dopant concentrations, and RF voltage conditions on detection performance. When toluene was used as the dopant, the method exhibited a good linear relationship (correlation coefficient R2 > 0.99) in the concentration range of 0.04-1.3 ppm, with a detection limit as low as 5.6 ppb. By testing tripe samples soaked in formaldehyde solutions of varying concentrations and durations, the method effectively detected formaldehyde residues in the tripe and identified methanol in the formaldehyde solutions. Furthermore, comparative analysis of rinsed and unrinsed samples confirmed the detection of persistent, tissue-bound residues, validating the method's robustness for real-world scenarios.