Combined analytical techniques for the analysis of complex consumer products and bio-samples

To meet the continuously changing demands of consumers, product innovation in foods and cosmetics industries has to be very fast. This thesis aims to develop novel analytical methods and strategies for safety and quality control, performance evaluation, claim substantiation and mode-of-action studies for consumer-preferred tea products and hair care formulations. Various analytical techniques that allow shorter analysis times, high data quality and low costs while meeting all externally dictated safety compliance requirements were selected for further method development. A UHPLC-MS/MS method combined with a QuEChERS sample preparation procedure was developed to analyze pesticide residues in tea. A UHPLC-UV method combined with SPE sample pre-treatment was proposed for the rapid quantification of L-theanine in RTD teas. Combined ESI-MS and 2D NMR was applied to investigate the inclusive interaction between β-cyclodextrin and EGCG in tea de-bittering. The efficacy of anti-dandruff (AD) shampoos depends on the deposition properties of the AD actives, e.g. climbazole (CBZ) and zinc pyrithione (ZPT), on the human scalp in the process of shampoo application and rinse-off. To support in vitro and in vivo studies for the performance evaluation of AD shampoos, several methods were proposed for measuring the amount and spatial distribution of CBZ and ZPT retained on human scalp by UHPLC-MS/MS, SEM and Raman. In addition, a method combining tape strip sampling and SEM/EDX measurement was proposed for measuring and visualizing the particle size, morphology and composition of ZPT particles deposited on human scalp.