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Determination of nalidixic acid using dispersive liquid-liquid microextraction followed by HPLC-UV

100%

Daneshfar A. , Lotfi H. J. , Khezeli T.

tom Vol. 23, no. 4

567--577

A fast, simple, and sensitive sample preparation procedure based on dispersive liquid-liquid microextraction (DLLME) followed by high-performance liquid chromatography and ultraviolet (HPLC-UV) detection was developed for the determination of nalidixic acid in a human urine sample. A mixture of extraction solvent (35 μL carbon tetrachloride) and disperser solvent (1.0 mL acetonitrile) were rapidly injected into an aqueous sample (5.0 mL) for the formation of cloudy solution; the analyte in the sample was extracted into the fine droplets of carbon tetrachloride. After extraction, phase separation was performed by centrifugation and the enriched analyte in the sedimented phase was determined by HPLC-UV. The influence of several important parameters on extraction efficiency of nalidixic acid was evaluated. Under optimized experimental conditions, the calibration graph was linear in the concentration range of 1–800 μg L-1 with the coefficient of determination being 0.9994. The limits of detection and quantification were 0.2 and 0.7 μg L-1, respectively. The relative standard deviations (RSDs) and accuracies were in the range of 1.1–8.7% and 92.7–104.9%, respectively. This procedure was successfully applied to the determination of nalidixic acid in spiked urine samples with satisfactory results. The relative recoveries of urine samples ranged from 103.1% to 105.1%, with RSDs varying from 0.8% to 2.4%.

Application of dispersive liquid—liquid microextraction for the analysis of organophosphorus pesticides in Hawthorn (Crataegus pinnatifida var. major) juice samples

88%

Ren Q. , Xia T.

2016

tom Vol. 28, no. 3

403--414

Dispersive liquid–liquid microextraction (DLLME) coupled with gas chromatography equipped with flame photometric detection (GC—FPD) is introduced to extract and determine the fifteen organophosphorus pesticides (OPPs) in hawthorn (Crataegus pinnatifida var. major) juice samples. Some parameters affecting the DLLME efficiency, such as the type and volume of extraction and dispersive solvents, extraction time, and salt concentration, were studied and optimized. The optimized extraction and dispersive solvents are trichloroethane and acetonitrile, respectively. Good linearity was ranged from 0.5 to 100 ng mL−1 with correlation coefficients from 0.9991 to 0.9999. The limits of quantification (LOQs) varied from 0.15 to 0.3 ng mL−1, and the limits of detections (LODs) ranged from 0.05 to 0.1 ng mL−1. The relative standard deviations (RSDs) varied from 1.0% to 2.8% (n = 6) with the relative recoveries in the range of 85.6–119.1%. The method was successfully applied in the determination of OPPs in ten commercial hawthorn juice samples. The chlorpyrifos was detected in one sample.

Development of ultrasound-assisted extraction followed by solid-phase extraction followed by dispersive liquid–liquid microextraction followed by gas chromatography for the sensitive determination of diazinon in garden parsley as vegetable samples

88%

Rezaee M. , Khalilian F. , Pourjavid M. R.

Acta Chromatographica

2023

tom Vol. 35, no. 4

347--353

A new pretreatment method termed ultrasound-assisted extraction (UAE) which is combined with solid-phase extraction which is combined with dispersive liquid-liquid microextraction (SPE-DLLME) followed by gas chromatography-flame ionization detector (GC-FID) analysis has been developed for the determination of diazinon in garden parsley as vegetable samples. The analyte was extracted from garden parsley sample using ultrasound-assisted extraction followed by solid-phase extraction followed by dispersive liquid-liquid microextraction. Various parameters that affect the efficiency of the extraction techniques have been optimized. The calibration plot was linear in the range of 5.0–1,000 μg kg⁻¹ with detection limit of 1.0 μg kg⁻¹ for diazinon in garden parsley samples. The results confirm the suitability of the UAE-SPE-DLLME-GC-FID as a sensitive method for the analysis of the targeted analyte in garden parsley samples.