Simultaneous identification of 18 illegal adulterants in dietary supplements by using high-performance liquid chromatography-mass spectrometry.

We developed a method for the identification of 18 illegal adulterants in dietary supplements for erectile dysfunction by using high-performance liquid chromatography-mass spectrometry. The separation was achieved on a Cosmosil 3C18-EB column. The mobile phase consisted of 0.1% formic acid solution and 0.1% formic acid in acetonitrile, with gradient elution at a flow rate of 0.15 mL/min. The proposed method may be useful for the identification of illegal adulterants and for quality control of dietary supplements.

Simultaneous determination of 11 preservatives in cosmetics by high-performance liquid chromatography.

Preservatives prevent the growth of microorganisms in foods, pharmaceuticals and cosmetics. There exist numerous restrictions regarding the maximum allowable levels of preservatives in cosmetics. We analyzed 11 regulated preservatives in commercial cosmetics and manufacturers need to analyze their products for quality control purposes. However, methods used in previous studies to date have been inadequate for use by public institutions and manufacturers. Therefore, an effective, scalable method for the analysis of preservatives in cosmetics is required. We developed a novel method for the simultaneous determination of 11 regulated preservatives in cosmetics by high-performance liquid chromatography (HPLC). We applied the samples to a C18 column in a simple mobile phase (5 mmol/L ammonium formate solution and acetonitrile) with gradient elution at a flow rate of 1.0 mL/min at a single wavelength (230 nm). The correlation coefficients of the calibration curves were >0.997. The percent recoveries were 92.8-111.9% and the relative standard deviations were <4.3% (n = 6). The peak resolution for all preservatives was >1.9. Because of the simple conditions for isolation and complete separation, the HPLC method can be effectively applied to the analysis of preservatives in commercially retailed cosmetics.

Simultaneous identification of hydroxythiohomosildenafil, aminotadalafil, thiosildenafil, dimethylsildenafil, and thiodimethylsildenafil in dietary supplements using high-performance liquid chromatography-mass spectrometry.

We developed a method for the separation and identification of illegal adulterants (hydroxythiohomosildenafil, aminotadalafil, thiosildenafil, dimethylsildenafil, and thiodimethylsildenafil) from dietary supplements using high-performance liquid chromatography-mass spectrometry. The separation was achieved on a C18 column: the mobile phase consisted of 5 mM ammonium formate (pH 6.3)-acetonitrile (75 : 25, v/v) and acetonitrile, with gradient elution at a flow rate of 0.2 mL/min. The proposed method could also be used to separate vardenafil, homosildenafil, and dimethylsildenafil, all of which have the same molecular weight. Furthermore, the proposed method could simultaneously separate hydroxythiohomosildenafil, aminotadalafil, thiosildenafil, dimethylsildenafil, thiodimethylsildenafil, vardenafil, and homosildenafil. Thus, this method may be useful to identify medicinal ingredients for erectile dysfunction and their analogs and to control the quality of dietary supplements.

A simple and selective detection method for aristolochic acid in crude drugs using solid-phase extraction.

The official Japanese method for analyzing aristolochic acid I (AA-I) in Asiasarum root using conventional high-performance liquid chromatography (HPLC) is described in the Japanese Pharmacopoeia, Sixteenth Edition. Interfering peaks of AA-I sometimes appear after HPLC analysis of crude drugs. A selective analytical method is needed to determine definitively whether AA-I is present in crude drugs. In this study, we developed a selective method that combined solid-phase extraction and liquid chromatography/mass spectrometry (LC/MS) which may be useful for identifying AA-I in crude drugs and for quality control.