Levels of residues and dietary risk assessment of the fungicides myclobutanil, penconazole, tebuconazole, and triadimenol in squash.

Triazole fungicides may potentially harm human health. The 'quick, easy, cheap, effective, rugged, and safe' approach has become popular for extraction and cleanup during pesticide residue analysis. We aimed to (a) validate a method for the simultaneous determination of myclobutanil, penconazole, tebuconazole, and triadimenol in squash using LC-MS/MS and (b) determine the pre-harvest intervals (PHIs) and assess the related risk of consuming squash cultivated under open-field conditions in Saudi Arabia. Using acetonitrile as the extraction solvent and fourfold dilution in deionized water led to weak signal suppression (<-6.1%). The limits of quantitation ranged from 10 to 40 µg/kg. Mean recovery and relative standard deviation ranged from 81.7 to 96.3% and from 3.6 to 11.4%. The half-lives ranged from 2.22 to 3.83 days, and the dissipation followed first-order kinetics. The terminal residues of myclobutanil, penconazole, tebuconazole, and triadimenol were <0.771, <0.307, <0.459, and <0.954 mg/kg, respectively, 7 days after two or three applications of recommended dosages. The PHIs of 7.1-11.4, 8.7-13.1, 3.8-5.3, and 11.3-14.3 days are suggested after the application of the recommended dose and double the recommended dose. A consumer risk assessment based on estimated dietary intake indicated that the consumption of squash treated with the recommended doses does not pose a significant health risk.

Monitoring pesticide residues in dates marketed in Al-Qassim, Saudi Arabia using a QuEChERS methodology and liquid chromatography-tandem mass spectrometry.

A sensitive, simple and rapid QuEChERS extraction method and liquid chromatography equipped with triple quadrupole mass spectrometry (LC-MS/MS) were used to determine 42 pesticides in dates. Acidified acetonitrile and citrate buffer salts were used to extract re-hydrated samples. Acceptable validation performances were achieved, i.e. recovery range of 70-120% and RSD values ≤20% for 42 analytes at three different concentrations:100, 50 and 10 µg/kg. This method was used to analyse 200 date fruit samples (var. Sukkari) collected from different large markets in the Al-Qassim region in Saudi Arabia. Pesticide residues were detected in 36 (18%) of the date fruits samples, and 15 samples (7.5%) exceeded the maximum residue levels. The ruggedness test results showed that this method is robust and suitable for the determination of pesticide residues in dates. Additionally, the results showed that the monitored dates did not have a health impact on consumers in Saudi Arabia during the study period.