Detection of Pesticide Residues on the Surface of Fruits and Vegetables Under Different Washing Methods Based on Hand-Held Ion Source

In recent years, with the increasing concern of food safety and the continuous improvement of pesticide residue standards, the maximum allowable limits of pesticide residue have gradually been reduced. This has led to higher requirements for rapid and efficient detection of pesticide residues on the surface of fruits and vegetables. Mass spectrometry has the advantages of high sensitivity, specificity, and ability to detect multiple components. However, the use of traditional mass spectrometry can be challenging for novice users. Previous studies have mainly relied on bulky and expensive mass spectrometer or chromatograph, which require trained personnel to operate. By combining hand-held ion source with portable mass spectrometer, a low-cost and rapid on-site method for pesticide residue detection can be achieved, potentially enabling non-professionals to detect chemicals on-site without training. This study based on the combination of a hand-held ion source and a commercial mass spectrometer was expected to evaluate the effectiveness of different washing methods for removing pesticide residues from the surface of fruits and vegetables. The effects of different washing methods on the removal of pesticide residues were investigated for cherry tomatoes and leek treated with two different pesticide concentrations. The results showed that there was no universally optimal washing method applicable to different pesticide residues on the surfaces of different fruits and vegetables. The four washing methods explored in this study had certain effects on the removal of atrazine or dimethoate pesticide residues from cherry tomatoes and leek, but there were differences under different pesticide types, concentrations, and types of fruits and vegetables. Specifically, among the high-concentration pesticide-treated groups, washing with dishwashing detergent was found to be the most effective method for removing pesticide residues from cherry tomatoes, although it was not as effective for leek. For the low-concentration pesticide-treated groups, cherry tomatoes showed optimal washing after soaking in brine, while leek preferred water. Furthermore, this study also highlighted the superiority of hand-held ion source for detecting pesticide residues on the surface of fruits and vegetables in everyday scenarios. This method has the potential to offer a low-cost, simple, and fast detection technique that can be valuable for food safety and environmental monitoring, etc, and has significant practical application value.