Adulterated premixed coffees have turned into an issue in Malaysia lately and have caught the eye of the authorities due to death reports linked to these products. The major cause of this issue is reported that these premixed coffees have passed food inspection test and eventually released to the market for public consumption. These coffees were claimed to be spiked with several sexual enhancers like sildenafil, tadalafil, and vardenafill, which are common drugs used to treat erectile dysfunction. Methods: Chemometrics approach using UV-Vis spectroscopy was developed to detect the selected sexual enhancer drugs found in commercial coffees by employing SIMCA-P software for the multivariate statistical analysis. Seven brands of coffee samples were purchased from local stores, and 30 sachets each were tested, hence totalling to 210 samples. Each sample was named H, J, G, W, N, T, and K, respectively. Results: Three multivariate models were generated, namely principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA), and partial least squares discriminant analysis (PLS-DA). OPLS-DA was selected as the best model for the overall results as it displayed minimal discriminate. Sildenafil, tadalafil, and vardenafil were detected in sample H, while vardenafil in brand J, and none in samples G, W, N, T, and K. Conclusion: OPLS-DA analysis showed discrimination for the sexual enhancer drugs in two brands of premixed coffee. The UV-Vis spectroscopy-based chemometrics method proved to be reliable and efficient in determining the selected drugs, as well as in saving time and cost.
Sildenafil and its analogues (tadalafil and vardenafil) are phosphodiesterase type 5 inhibitors used in the treatment of male erectile dysfunction. Some dietary supplements, herbal preparations and food products which claim to enhance male sexual function have been found to be adulterated with these drugs. In this study, a gas chromatograph-mass spectrometer (GC-MS) assay was developed for identification of the drugs. In addition to good and short chromatographic separation that can be achieved within 6 min by using a short 10 m capillary column, no prior sample clean-up before GC-MS analysis was required, thus making this assay a cost saving and rapid method. Furthermore, the assay is specific as the identification of sildenafil, tadalafil and vardenafil were done by detection of molecular ions; m/z 474, 389 and 488, [corrected] respectively, and several other characteristic ions resulted from the mass fragmentation of individual molecules. Using our currently developed assay, sildenafil and its analogues were successfully identified in food and herbal matrices.