HOLLOW FIBER-BASED LIQUID PHASE MICROEXTRACTION COUPLED WITH HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY FOR EXTRACTION AND DETERMINATION OF VITAMIN D₃ IN BIOLOGICAL FLUIDS

Abstract

The reliability of hollow fiber-based on using two immiscible organic solvents in the lumen and wall pores of hollow fiber was evaluated for extraction and preconcentration of trace amount of vitamin D₃, prior to determination by HPLC-UV. The analyte was extracted from a 8-mL sample solution, into a thin layer of an organic solvent (n-dodecane) impregnated in hollow fiber pores, and finally back-extracted into a µL volume of organic solvent (acetonitrile) located inside the lumen of the hollow fiber. The effects of several factors such as the nature of organic solvent, hollow fiber length, stirring speed, extraction time, ionic strength, sample volume, and extraction temperature on the enrichment factor_s (EF_s) were investigated. Under optimized conditions, the enrichment factor of 130, limit of detection (LOD) of 0.9 ng mL⁻¹ were obtained. The calibration curve was linear within the range of 3 to 1000 ng mL⁻¹ with reasonable linearity (R² = 0.999).

The percentages of relative within-day and between-day standard deviations (RSD %) based on six replicated determinations were 5.4 and 6.1, respectively. Finally, the feasibility of the proposed method was successfully evaluated by extraction, and determination of the analyte in the biological fluids and satisfactory results were obtained.

Keywords:

• biological fluids
• fat-soluble vitamins
• high-performance liquid chromatography
• hollow fiber liquid phase microextraction
• immiscible organic solvents
• vitamin D₃

Notes

^a Molecular weight.

^b Melting point(°C).

Conditions: 10 mL of 100 ng mL⁻¹vitaminD₃; stirring speed: 500 rpm; extraction time: 25 min; salt addition, no NaCl added; room temperature.

^a EF and ER were obtained at 50 ng mL⁻¹ level of the analyte.

^b concentration in ng mL⁻¹.

^a Results are presented as mean ± sd, n = 6.

^a Concentration was reported as ng mL⁻¹.

^b Concentration was reported as mg L⁻¹.

^c Concentration was reported as µg/100 g.

^d Liquid–Liquid extraction high performance liquid chromatography with UV-DAD detector.

^e Solidified floating organic drop microextraction high performance liquid chromatography with UV-DAD detector.

^f Solid phase extraction high performance liquid chromatography with UV detector.

^g Solid phase extraction high performance liquid chromatography with UV detector and liquid chromatography with MS/MS detector.