Determination of free fatty acids in chocolate by liquid chromatography with tandem mass spectrometry.
This paper describes a rapid extraction method, based on a matrix solid-phase dispersion technique using diatomaceous earth as solid support and 50:50 (v/v) chloroform/methanol as extracting solvent, that can determine 11 free fatty acids in chocolate. The extraction procedure is followed by reversed-phase liquid chromatography/tandem mass spectrometry (LC/MS/MS) using a normal-bore (4.6 mm i.d.) C-18 column and an electrospray interface operating in the negative ion mode. The tandem mass spectra of selected compounds show that charge-remote fragmentation (CRF) mechanisms are occurring; the intensities of the CRF reactions increase with the carbon number and degree of unsaturation of the fatty acids. Average recoveries, evaluated by the standard addition method, vary between 79-103%, and the estimated quantification limits are less than 153 ng/g. The proposed method has been used to analyse nine chocolate samples from various price ranges, bought from supermarkets.
Laboratorio Chimico per la Sicurezza, Dipartimento di Chimica, Università La Sapienza, Piazzale Aldo Moro 5, P.O. Box 34, Posta 62, 00185 Rome, Italy.
Daniela
D
Perret
Alessandra
A
Gentili
Stefano
S
Marchese
Manuel
M
Sergi
Lidia
L
Caporossi
D002099:Cacao / Q000737:chemistry*; D002182:Candy; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005230:Fatty Acids, Nonesterified / Q000032:analysis* / Q000145:classification; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
D005230:Fatty Acids, Nonesterified