| Abstract: | Preconcentration of trace amounts of diazinon by carbon mesoporous CMK‐3 in water and biological samples and measurement by high‐performance liquid chromatography were investigated. CMK‐3 was prepared using hexagonal SBA‐15 as the template. The synthesized materials were characterized by X‐Ray diffraction (XRD), Fourier transform infrared spectroscopy, Brunaur–Emmet–Teller, transmission electron microscopy and Boehm titration method. The preconcentration procedure was optimized using a multivariate optimization approach following a two‐stage process. The effect of analytical parameters including the amount of the CMK‐3 as an adsorbent, pH, type and volume of eluent and flow rate of eluent and sample were studied by a screening project, then the effective parameters were optimized by response surface methodology based on central composite design. The average extraction efficiency of diazinon under optimal conditions (CMK‐3 dosage = 25 mg, sample flow rate = 2.5 mL min−1, eluent flow rate = 1.25 mL min−1, volume of methanol as an eluent =3.5 mL and initial pH = 6) was 97.11%, which agrees well with the predicted response value (97.93%). The linearity of the method was in the range of 0.5–100 μg L−1 with a correlation coefficient of 0.997. Enrichment factor, limit of detection and limit of quantification were 285.7, 0.09 and 0.23 μg L−1, respectively. The relative standard deviation (RSD) under optimum conditions was 2.21% (n = 5). The proposed method was applied to determine diazinon in real water and biological samples. Recovery of diazinon from real samples was between 95.80 and 104.94% with an RSD of 0.19–4.65%. Thus, this method is suitable for the preconcentration and determination of diazinon in real water and biological samples. |
