Characteristic fingerprint based on gingerol derivative analysis for discrimination of ginger (Zingiber officinale) according to geographical origin using HPLC-DAD combined with chemometrics.

Chromatographic fingerprints of gingers from five different ginger-producing countries (China, India, Malaysia, Thailand and Vietnam) were newly established to discriminate the origin of ginger. The pungent bioactive principles of ginger, gingerols and six other gingerol-related compounds were determined and identified. Their variations in HPLC profiles create the characteristic pattern of each origin by employing similarity analysis, hierarchical cluster analysis (HCA), principal component analysis (PCA) and linear discriminant analysis (LDA). As results, the ginger profiles tended to be grouped and separated on the basis of the geographical closeness of the countries of origin. An effective mathematical model with high predictive ability was obtained and chemical markers for each origin were also identified as the characteristic active compounds to differentiate the ginger origin. The proposed method is useful for quality control of ginger in case of origin labelling and to assess food authenticity issues.

Efficient hydrophilic interaction liquid chromatography-tandem mass spectrometry for the multiclass analysis of veterinary drugs in chicken muscle.

A simple and sensitive method has been developed for multiresidue analysis of 24 important veterinary drugs (including 3 aminoglycosides, 3 ß-lactams, 2 lincosamides, 4 macrolides, 4 quinolones, 4 sulfonamides, 3 tetracyclines, and amprolium) in chicken muscle. The method involved a simple extraction using (1:1, v/v) of 2% trichloroacetic acid in water-acetonitrile, followed by removing fat with hexane, dilution of sample extract, and filtration prior to liquid chromatography-tandem mass spectrometric (LC-MS/MS) analysis. Hydrophilic interaction liquid chromatography (HILIC) proved to be very effective for separation of a wide range of polar and hydrophilic compounds (providing high sensitivity and good peak shape) compared to reversed phase and ion-pair separation. The method was successfully validated according to the European Decision 2002/657/EC. Average recoveries were 53-99% at 0.5-MRL, MRL, and 1.5-MRL spiking levels, with satisfactory precision ≤15% RSD. The limit of detection of the method was 0.1-10 µgkg(-1) for 22 analytes and 20 µgkg(-1) for aminoglycosides. These values were lower than the maximum residue limits (MRLs) established by the European Union. The evaluated method provides reliable screening, quantification, and identification of 24 veterinary drug residues in foods of animal origin. It has been successfully tested in real samples (such as chicken muscle, shrimp, and egg).