Development and validation of a method for simultaneous analysis of hair underivatized amino acids and damage biomarkers, using liquid chromatography-tandem mass spectrometry.

The forensic and medical fields are seeing growing interest in the amino acid and damage biomarker composition of hair, in order to identify adulteration of drug hair testing and for diagnostic purposes. Therefore, there is an increased demand for quick and accurate analytical methods. This study presents the first liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for the simultaneous quantification of hair amino acids and four damage biomarkers, which also implements an isotopic dilution strategy to improve recovery and precision of the acid hydrolysis-sensitive analytes.

Persulfate Reaction in a Hair-Bleaching Formula: Unveiling the Unconventional Reactivity of 1,13-Diamino-4,7,10-Trioxatridecane.

The stability and unconventional reactivity of 1,13-diamino-4,7,10-trioxatridecane in the presence of NH, HO, and (NH)SO are described. The ether-diamine is an ingredient marketed to hair salons and consumers for so-called "plex" services to compensate for hair damage during bleaching. The main reaction product identified is an unexpected azanyl ester derivative.

Photochemistry of Diaryl Vicinal Tetraketones and Chemistry of Intermediate (Aroyloxy)arylketenes(1).

Photolysis of diaryl vic-tetraketones results in formation of tricyclic-gamma-lactones 3 and 4 with low quantum but high chemical yield. (Aroyloxy)arylketenes and carbon monoxide are the initial photochemical products of these photolyses. Subsequent reaction of ketene with ground-state tetraketone results in formation of the observed photoproducts via intermediate beta-lactones.