Solid‐phase extraction assisted dispersive liquid–liquid microextraction based on solidification of floating organic droplet to determine sildenafil and its analogues in dietary supplements

• Published in: Journal of separation science 2017-08, Vol.40 (15), p.3120-3129
• Main Authors: Li, Jing, Roh, Si Hun, Shaodong, Jia, Hong, Ji Yeon, Lee, Dong‐Kyu, Shin, Byong‐kyu, Park, Jeong Hill, Lee, Jeongmi, Kwon, Sung Won
• Format: Article
• Language: English
• Subjects: adulteration; Dietary supplements; Dietary Supplements - analysis; Dispersion; Extraction processes; ion‐pairing chromatography; Limit of Detection; Linearity; Liquid chromatography; Liquid Phase Microextraction; Liquid-liquid extraction; Mathematical analysis; mixed‐mode solid‐phase extraction; Regression analysis; reversed‐phase dispersive liquid‐liquid microextraction; Sildenafil; Sildenafil Citrate - analogs & derivatives; Sildenafil Citrate - analysis; Solid Phase Extraction; Solidification; Solids; Ultraviolet detectors
• ISSN: 1615-9306; 1615-9314
• DOI: 10.1002/jssc.201700159

A novel analytical method for the simultaneous determination of the concentration of sildenafil and its five analogues in dietary supplements using solid‐phase extraction assisted reversed‐phase dispersive liquid–liquid microextraction based on solidification of floating organic droplet combined with ion‐pairing liquid chromatography with an ultraviolet detector was developed. Parameters that affect extraction efficiency were systematically investigated, including the type of solid‐phase extraction cartridge, pH of the extraction environment, and the type and volume of extraction and dispersive solvent. The method linearity was in the range of 5.0–100 ng/mL for sildenafil, homosildenafil, udenafil, benzylsildenafil, and thiosildenafil and 10–100 ng/mL for acetildenafil. The coefficients of determination were ≥0.996 for all regression curves. The sensitivity values expressed as limit of detection were between 2.5 and 7.5 ng/mL. Furthermore, intraday and interday precisions expressed as relative standard deviations were less than 5.7 and 9.9%, respectively. The proposed method was successfully applied to the analysis of sildenafil and its five analogues in complex dietary supplements.