Simultaneous determination of 3,4-dimethoxybenzaldehyde and 3,4-dimethoxyphenylacetone in industrial waste waters by high-performance liquid chromatography-diode array detection

Determination of four flavorings in infant formula by solid-phase extraction and gas chromatography-tandem mass spectrometry

Increasing attention has been focused on the artificial flavorings added in foods, especially those for infants and children. For the first time, a sensitive and efficient analytical method based on gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed for the simultaneous identification and quantification of four flavoring agents (vanillin, methylvanillin, ethylvanillin, and coumarin) in infant formula samples. The flavorings in samples were extracted with methanol/water (v/v, 1:1), cleaned up by solid-phase extraction, and determined by GC-MS/MS in selected reaction monitoring (SRM) mode. Both isotope-labeled internal standards and matrix-matched calibration solutions were used to correct the matrix effects. The limit of quantification (LOQ) was calculated as 10 times the standard deviation, and it was 10.0 μg kg (-1) for vanillin, methylvanillin, ethylvanillin, and coumarin. The average recoveries were in the range of 82.8-107.5% with relative standard deviations (RSDs) below 8.9% measured at three concentration levels (10, 50, and 100 μg kg(-1)). The proposed method is suitable for the sensitive and accurate simultaneous determination of four flavoring agents in infant formula samples and also provided potential use for reference in terms of real analysis of other foods.

Retention characteristics and practical applications of carbon sorbents

Reversed-phase separations provides a versatile technique in high-performance liquid chromatography. Porous graphitized carbon (PGC) support shows unique retention characteristics. Separations on PGC columns use typical reversed-phase eluents (water and organic modifiers miscible with water), however, the retention order of solutes generally does not follow their hydrophobicity order. Molecular hydrophobicity influences but not determines the elution order of any set of solutes. The properties of these supports, mechanisms of retention and application are discussed, along with correlations which can guide the choice of solvent combinations for typical separations.