Wyniki wyszukiwania - BazTech

1

Dispersive liquid-liquid microextraction followed by high-performance liquid chromatography as an efficient and sensitive technique for determination of nandrolone and testosterone in human urine

Rezaee Mohammad

Acta Chromatographica

|

2023

|

Vol. 35, no. 1

28--34

EN

Dispersive liquid-liquid microextraction (DLLME) and high performance liquid chromatography – UV detection was presented for extraction and determination of nandrolone and testosterone in human urines. Chloroform at microliter volume level and acetonitrile were used as extraction and dispersive solvents, respectively. The main advantages of method are high speed, high enrichment factor, high recovery, good repeatability and extraction solvent volume at µL level. The influence of several variables (e.g. type and volume of disperser and extraction solvents, ionic strength, etc.) on the performance of the sample preparation step was carefully evaluated. Under the optimum conditions, the calibration graphs were linear in the range of 5–500 μg L⁻¹ with detection limit of 2.5 μg L⁻¹ for both of them. The relative standard deviation (R.S.D.s) for five replicate measurements of nandrolone and testosterone were 9.4% and 8.8%, respectively. The relative recoveries of nandrolone and testosterone in urine sample at spiking level of 25.0 μg L⁻¹ are ranged between 86.4% and 98%. DLLME combined with HPLC-UV is a fast, simple and efficient method for the determination of nandrolone and testosterone in human urines.

2

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

Rezaee Mohammad, Khalilian Faezeh, Pourjavid Mohammad Reza

Acta Chromatographica

|

2023

|

Vol. 35, no. 4

347--353

EN

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.

3

Development of magnetic solid-phase extraction coupled with dispersive liquid–liquid microextraction method for the simultaneous determination of biphenyl and biphenyl oxide in water Samales

Noori Arezoo Hassan, Rezaee Mohammad, Kazemipour Maryam, Mashayekhi Hossein Ali

Acta Chromatographica

|

2019

|

Vol. 31, no. 1

1--7

EN

A new and sensitive method, termed magnetic solid phase extraction combined with dispersive liquid–liquid microextracton (MSPE–DLLME), has been developed for the simultaneous determination of biphenyl and biphenyl oxide in water samples. Different parameters influencing the extraction efficiency, including the amount of sorbent, sorption time, type of elution solvent and its volume, type of extraction solvent and its volume, and elution time were optimized. The calibration curves were linear in the range of 0.5–100 μg/L for both of them. The limits of detection (LODs) were achieved, 0.03 μg/L for biphenyl and 0.07 μg/L for biphenyl oxide, respectively. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of biphenyl and biphenyl oxide in sea, river, tap, and water well.