Optimization and Validation of a novel Nebulizer-assisted Liquid Phase Microextraction Followed by HPLC-DAD for Diazinon Analysis in Plasma Samples

Diazinon is among the most prevalently used broad-spectrum organophosphates insecticides. Diazinon toxicity depends on its blood concentration. The current study aimed to extract and determine diazinon in plasma samples using a new Nebulizer -Assisted Liquid-Phase Microextraction followed by High-Performance Liquid Chromatography with Diode-Array Detection (NALPME-HPLC-DAD).

Several effective parameters, including the type and volume of extracting solvent, pH, surfactant, salt amount, and nebulizing, were evaluated and optimized to find the best condition for the extraction and determination of diazinon in plasma samples using High-Performance Liquid Chromatography with Diode-Array Detection (HPLC-DAD). Additionally, the Plackett-Burman design was employed in preliminary experiments to screen the most appropriate parameters. Furthermore, we selected a central composite design to determine the best experimental conditions in NALPME-HPLC-DAD.

In an optimum condition, 412 μL of toluene (as extracting solvent) and nebulizing with nitrogen gas as dispersing and emulsification, sodium lauryl sulfate (2.8% w/v) and 100μL sodium chloride (1.5% w/v) in pH 8.1 were selected. The standard calibration curves for diazinon were linear with the concentration range of 0.5–4 µg/mL with a correlation coefficient of 0.9992. The Limit Of Detection (LOD) and Limit Of Quantification (LOQ) for diazinon were 0.123 µg/mL and 0.372 µg/mL, respectively.

The proposed method was simple, accurate, precise, and sensitive for analyzing diazinon in the plasma samples. This method can be used for analyzing plasma diazinon concentrations in acute poisoning cases in clinical and forensic toxicology analyses.