Detection of adulteration and counterfeits in food supplements: development and validation of fast analytical methods

Adulterations and counterfeits represent an important problem in the market of food supplements. Dietary supplements are not subjected to any safety assessments prior to commercialization; therefore they can easily added with pharmaceutical drugs or analogue substances in order to increase product effectiveness. Food supplements for body weight reduction or for athletes are the products most frequently involved in illicit additions. Screening methods, such as High-Performance Thin-Layer Chromatography (HPTLC), are often the best analytical approaches to screen a large number of samples characterized by complex matrixes. Other analytical technique, such as High-Performance Liquid Chromatography (HPLC) coupled with different detectors, can be used to confirm and quantify the illicit additions. The aim of this work was the development and validation of different analytical approaches to detect adulterants in food supplements. Several dietary supplements confiscated by NAS (Comando Carabinieri per la Tutela della Salute) in different Italian gymnasiums were analyzed in order to detect steroid hormones and active amines; two HPTLC methods were set up for the screening analysis of these classes of compounds. The illicit compounds investigated were detected in 23% of the samples suspected for a possible adulteration. The more expensive mass spectrometry technique was applied only to the positive samples to confirm the presence of adulterants identified in screening analysis. HPTLC showed to be a fast and simple technique for the preliminary identification of adulterations in food supplements, representing an important tool for laboratories involved in food control. The use of expensive and sensitive techniques, such as HPLC coupled with mass spectrometry detector, can be limited only to the positive samples, allowing a wider control of the market by public institutions.