Determination of olive oil acidity by CE

Abstract

In this work, a CE method for the determination of olive oil acidity was proposed. The method was based on an ethanolic extraction (at 60 degrees C) of the oil long-chain free fatty acids (LC-FFAs) components followed by CE determination in pH 6.86 phosphate buffer at 15 mmol/L concentration containing 4 mmol/L sodium dodecylbenzenesulfonate (SDBS), 10 mmol/L polyoxyethylene 23 lauryl ether (Brij 35), 2% v/v 1-octanol and 45% v/v ACN under indirect UV detection at 224 nm. Although this electrolyte promoted baseline separation of myristic acid (C14:0) (internal standard (IS)) and olive oil major components (palmitic acid (C16:0), oleic acid (C18:1c) and linoleic acid (C18:2cc)) in less than 8 min, after a few injections, the electropherogram profiles were severely altered (peak broadening, migration time shifts, etc.) and the current increased substantially. An adsorption study was conducted revealing that the dissolution of the capillary external polyimide coating during the electrophoretic run caused the detrimental effect. After removal of the capillary tip coating, ten consecutive injections could be performed without any disturbances and this simple procedure was, therefore, implemented during quantitative purposes. The reliability of the proposed method was further investigated by the determination of acidity of an extra virgin olive oil sample in comparison to the established methodology (AOCS method Ca 5a-40, alkaline volumetric titration (AVT)). No statistical differences were found within 95% confidence level. A % acidity of 0.39 +/- 0.02 was found for the olive oil sample under consideration.

Analysis of Omega 3 Fatty Acid in Natural and Enriched Chicken Eggs by Capillary Zone Electrophoresis

“…13,15 In order to calculate RF, we obtained four analytical curves taking into account a random experiment in genuine triplicate using an C18:1c (ω9), C18:2cc (ω6), C18:3ccc (ω3) …”

“…Due to the importance of these fatty acids in human diet and the possibility of economic fraud, this work has as the main objective to apply CE as an auxiliary analytical tool able to distinguish between enriched and natural eggs using the ω fatty acid profile as a chemical marker. [13][14][15][16][17][18][19][20][21][22][23] Such fraud can be serious, since no visual difference is found between enriched and natural chicken eggs and, according to a price survey in the local market, a dozen enriched eggs can cost up to 2.0 times the price paid for a dozen natural eggs.…”

Comparative Study of the Lipid Profiles of Oils from Kernels of Peanut, Babassu, Coconut, Castor and Grape by GC-FID and Raman Spectroscopy

“…They are formed basically by saturated (SFA) and unsaturated (UFA) fatty acids, unsaponifiable matter and antioxidants, which makes them potentially attractive as sources of natural products for several applications in feeding and pharmacology. 1,2 The most common fatty acids in vegetable oils are oleic (C 18 Peanut (Arachis hypogaea) oil is rich in UFA (oleic, linoleic and linolenic acids) and poor in SFA, while its kernel is the major source of vegetable protein, dietary fiber, antioxidant vitamins, minerals and phytochemicals. 3 Babassu (Attalea speciosa) oil presents high levels of fats used in food and industrial applications, as the production of cosmetic, soap, detergent, glycerin, animal feed, lubricant and biofuel.…”

“…10,11 In ancient times, the homemade production of castor oil was disseminated by Brazilian countryside families, which had low financial resources and difficulty in the access of health care, for its anti-inflammatory, antioxidant and laxative properties. 12 Several analytical techniques can be applied in analysis and certification of vegetable oils such as liquid chromatography, 13,14 gas chromatography, 15-17 capillary electrophoresis, 18,19 nuclear magnetic resonance, [20][21][22] and near-infrared spectroscopy. 23,24 However, in the last decade vibrational spectroscopies have been presented as an alternative, since the analysis is fast and usually the sample preparation is very simple.…”

DETERMINATION OF Cu, Fe, Mn, Zn AND FREE FATTY ACIDS IN PEQUI OIL

“…12 In recent years, capillary zone electrophoresis (CZE) has been applied to the determination of major FA in samples such as edible oils, olive oil, soy oils, butter and margarine, with faster and simpler analytical methods since the derivatization reaction is not required during sample preparation. 12,14,15 However, there have been no studies in the literature involving the determination of FA in pequi oil by CZE. Furthermore, the free acidity, expressed according to the free fatty acid (FFA) content, is an important quality parameter of oil samples.…”