Identification of edible Bird’s nest with amino acid and monosaccharide analysis.

This study describes the approach of amino acid and monosaccharide combined with Hotelling T2 range plot to identify edible bird nests (EBN) and non-EBN. Prior to the approach, an analytical method was developed and validated to quantify monosaccharides in EBN. Hotelling T2 range plots of both compounds were successful in predicting the different types of EBN and differentiating EBN and non-EBN.

Structural elucidation of propoxyphenyl isobutyl aildenafil, adulterant in a health supplement using high-resolution Orbitrap mass spectrometry.

A new sildenafil analogue, propoxyphenyl isobutyl aildenafil has been found in trace quantity from one health supplement. It has been purified by preparative high performance liquid chromatography (HPLC). The structural elucidation of this compound has been carried out using high-resolution Orbitrap mass spectrometry under two fragmentation modes, namely High energy Collision Dissolution (HCD) and Collision Induced Dissolution (CID).

Metabolite profiling of edible bird's nest using gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry.

Rationale: Edible bird's nest (EBN) is a renowned food item in the Chinese community due to the therapeutic effects claimed to be brought about by its consumption. However, very little scientific information has been revealed to support these claims. Thus, metabolite profiling was performed to identify the metabolites and to relate them to the medicinal properties of EBN.

Safety and quality assessment of 175 illegal sexual enhancement products seized in red-light districts in Singapore.

Background: In recent years, there has been increasing interest in the use of herbs and supplements as an alternative to drugs used for the treatment of erectile dysfunction, in order to enhance sexual performance. Over the years, adverse events associated with the consumption of natural health products for sexual enhancement and the treatment of erectile dysfunction have been reported.

Objective: The objective of this work was to assess the safety and quality of 175 sexual enhancement health products seized from makeshift stalls in red-light districts of Singapore.

Isolation and identification of thiohomosildenafil and thiosildenafil in health supplements.

Two unknown compounds are detected and isolated from health supplements for the enhancement of sexual function. The structures of the unknown compounds are elucidated using high-resolution MS, ESI-MS/MS, NMR, UV and IR. One compound is identified as an analogue of sildenafil in which the oxygen atom is substituted with a sulfur atom in the pyrazolopyrimidine moiety, and an ethyl group instead of a methyl group is attached to the piperazinyl nitrogen.

Identification of benzamidenafil, a new class of phosphodiesterase-5 inhibitor, as an adulterant in a dietary supplement.

A sample labeled to be a natural herbal supplement for the enhancement of sexual function, was sent to Health Sciences Authority (HSA) of Singapore for testing. An unknown compound was detected and isolated from the product. The structure of the unknown compound was identified using LC-UV, high-resolution MS, ESI-MS/MS, IR, and NMR.

Determination of isopropyl-9H-thioxanthen-9-one in packaged beverages by solid-phase extraction clean-up and liquid chromatography with tandem mass spectrometry detection.

A simple method was developed and validated for the trace determination of 2-isopropylthioxanthone (ITX) in packaged drinks. Samples were extracted from the food matrix using acetonitrile:water (60:40, v/v), and further subjected to clean-up and preconcentration using solid-phase extraction prior to analysis by liquid chromatography-tandem mass spectrometry using multiple reaction monitoring (MRM) mode. The use of 2-isopropyl-[(2)H7]thioxanthen-9-one was incorporated into the method as an internal standard.

Single laboratory validation of a method for the determination of Bisphenol A, Bisphenol A diglycidyl ether and its derivatives in canned foods by reversed-phase liquid chromatography.

A method was developed and validated for the simultaneous determination of Bisphenol A (BPA), Bisphenol A diglycidyl ether (BADGE), BADGE-H2O, BADGE-2H2O, BADGE-H2O-HCl, BADGE-HCl, and BADGE-2HCl in canned food using reversed phase high-performance liquid chromatography (HPLC) with fluorescence detection; chromatographic separation of all seven analytes was achieved (Rs > or = 1.08) using HPLC gradient elution technique. Acetonitrile was used to extract the analytes from the food matrix before subjecting the samples to liquid-liquid extraction, solid-phase extraction for further clean-up and preconcentration prior to HPLC analysis.