Vegetables and Fruits Testing

Shuiying, R., Yun, G., Shun, F., & Yi, L. (2015). Analytical Methods, 7(21), 9130-9136.

Plant growth promoters (PGPs) are a class of plant growth regulators that are well known for their strong functionalities. Even at trace levels, they can trigger a variety of basic physiological processes, such as cell division, cell enlargement, pattern formation, tropic growth, flowering, fruiting, and seed formation. However, their residues at the harvest stage may have adverse impacts on humans and/or the environment. To protect people from contamination and potential negative health effects, many countries and international organizations have established maximum residue limits (MRLs) for certain PGPs in designated food commodities. Therefore, strict control of food commodities is required to ensure compliance with MRLs, and multi-residue extraction and detection methods are urgently needed.

An improved QuEChERS method was established for the simultaneous determination of ten commonly used PGPs, including 6-benzylaminopurine (6-BA), indole-3-butyric acid, 1-naphthaleneacetic acid, methyl 1-naphthaleneacetate, 2-(1-naphthyl)acetamide, chlorpyrifos, chlorfenapyr, 4-chlorophenoxyacetic acid, 2,4-dichlorophenoxyacetic acid (2,4-D), and gibberellic acid (GA3) in fruits and vegetables. The extraction solvent acetonitrile (MeCN) was acidified, the ultrasonic extraction step was increased, and the amount of PSA was reduced. Higher recoveries and better precision indicate that the improved QuEChERS method is highly feasible.

Yuan, Y., Han, Y., Han, D., Yang, C., & Yan, H. (2020). Food Control, 118, 107417.

Thidiazuron (TDZ) and Chlorpyrifos (CPPU) belong to a class of synthetic phenylurea pesticides that are widely used in vegetables and fruits (such as cucumbers and watermelons) to obtain the desired yield. TDZ can cause central nervous system depression and renal damage. Long-term exposure to CPPU can lead to protein metabolism disorders. Therefore, many countries have established maximum residue limits (MRLs) for TDZ and CPPU. Due to the existence of MRLs for phenylurea pesticides and their potential harm to human health, the determination of phenylurea pesticides in vegetables and fruits is of great importance.

A rapid, low-cost, and miniaturized ultrasound-assisted dispersive filtration extraction (UADFE) combined with high-performance liquid chromatography (HPLC) method was used for the determination of phenylurea pesticides in vegetables and fruits. The UADFE method achieves rapid extraction through the dispersive solid-phase extraction (DSPE) mode, rapid separation through the filtration solid-phase extraction (FSPE) mode, and rapid elution by quickly switching between the DSPE and FSPE modes. The method can successfully determine phenylurea pesticides in various vegetables and fruits, proving its ability to ensure food safety and assess the potential risks of vegetables and fruits.

Li, G., Wen, A., Liu, J., Wu, D., & Wu, Y. (2021). Food Chemistry, 337, 127974.

Organophosphorus pesticides (OPPs) are a class of phosphate or thiophosphate ester compounds, which are one of the world's ten most famous pesticides. Due to their broad insecticidal spectrum and low persistence, OPPs have been widely used in various field crops to improve quality and yield. However, the abuse of OPPs can lead to agricultural product contamination and even potential harmful residual effects. OPPs are considered highly toxic compounds, which can endanger consumers even at low concentrations by inhibiting acetylcholinesterase and altering cholinergic signal transduction. Furthermore, the individual effects of OPPs, including mutagenic, carcinogenic, teratogenic, cytotoxic, genotoxic, and immunotoxic effects, have been scientifically demonstrated. Therefore, the accurate determination of OPPs in vegetable matrices is crucial for food safety.

A simple and effective sample pretreatment method based on Fe₃O₄@COF@Zr⁴⁺ was used to simultaneously quantify the residues of seven OPPs in vegetable samples by GC-FPD.

Narenderan, S. T., S. N. Meyyanathan, and B. J. F. R. I. Babu. Food Research International 133 (2020): 109141.

In recent years, gas chromatography and liquid chromatography have become the most commonly used methods for the detection and quantitative analysis of pesticide residues in fruits and vegetables due to their high sensitivity, separation, and identification capabilities. Furthermore, enzyme-linked immunosorbent assay (ELISA) and capillary electrophoresis (CE) have also been employed as alternative methods for detecting pesticide residues in authentic samples.

Gas Chromatography (GC): Most published research has shown that pesticide detection is carried out using gas chromatography coupled with various detectors. Due to its high sensitivity, detectors such as electron capture detector (ECD), flame photometric detector, nitrogen-phosphorus detector (NPD), and mass spectrometry (MS) are used.

Liquid Chromatography (LC): In the analysis of pesticide residues, various techniques based on liquid chromatography have been proposed, most of which are coupled with ultraviolet (UV), photodiode array (PDA), diode array detector (DAD), and mass spectrometry (MS) detectors.

Other Detection Methods: Techniques such as CE and ELISA are rapid and low-cost separation and detection methods in pesticide analysis. ELISA is based on the principle of antigen-antibody interaction to determine pesticides, and can provide high sensitivity and selectivity for a specific type of pesticide. CE is a valuable technique that requires fewer reagents and sample quantities, allowing for higher separation efficiency in a shorter time.