Capillary electrophoresis food additives

Carmine extracted from cochineal insects is one of the most used natural colorings for beverages and other foods. Some representative articles refer to isolation and spectrometric analysis or the use of HPLC or capillary electrophoresis (CE) to separate and characterize all cochineal pigments. Its active ingredient, carminic acid, was quantified by rapid HPLC-DAD or fluorescence spectrometry. Carminic acid, used as an additive in milk beverages, was separated within 9 min using a high-efficiency CE separation at pH 10.0 after a previous polyamide column solid phase extraction (SPE), ... 

Boyce, M.C., Determination of additives in food by capillary electrophoresis. Electrophoresis, 22, 1447, 2001. 

Food Additives and Contaminants Fresenius Journal of Analytical Chemistry Journal of Agricultural and Food Chemistry Journal of AO AC International Journal of Capillary Electrophoresis Journal of Chromatography A Trends in Analytical Chemistry Z. Lebensmittel Unters Forsch... 

The hyphenation of CE and NMR combines a powerful separation technique with an information-rich detection method. Although compared with LC-NMR, CE-NMR is still in its infancy it has the potential to impact a variety of applications in pharmaceutical, food chemistry, forensics, environmental, and natural products analysis because of the high information content and low sample requirements of this method [82-84]. In addition to standard capillary electrophoresis separations, two CE variants have become increasingly important in CE-NMR, capillary electrochromatography and capillary isotachophoresis, both of which will be described later in this section. 

The reader is directed to Ref. 5, which makes an interesting comparison between HPLC and other analytical methodologies for the determination of carbohydrates in foods. Additionally, notable progress has been made in the application of high-performance capillary electrophoresis (HPCE) in this field (8-11). However, given the scope of this chapter, we will focus on the advantages and drawbacks of other chromatographic techniques versus HPLC. 

Bean, S. R., Lookhart, G L., and Bietz, J. A., Acetonitrile as a buffer additive for free zone capillary electrophoresis separation and characterization of maize (Zeamays L.) and sorghum (Sorghum bicolor L. Moench) storage proteins. J. Agric. Food Chem., 48, 318-327, 2000. 

Vickers, P. J., Braybrook, J., Lawrence, R, and Gray, K., Detecting tartrate additives in foods Evaluating the use of capillary electrophoresis, J. Food Composition Anal, 20, 252, 2007. 

However, additives are normally combined to complement and promote their activity as a result, it is necessary to develop analytical methods for the determination of additive mixtures. Although some spectroscopic and chemical methods are used, it is preferable to use separation methods for this purpose. Most analytical methods used to determine food additives are based on chromatographic techniques, although several recent papers have demonstrated the usefulness of electrophoresis for the analysis of food colors, sweeteners, antioxidants, and/or preservatives. The separation of food colors has received most attention, with a number of articles published on both capillary zone electrophoresis and micellar electrokinetic chromatography. 

Hydroxypropyl cellulose (HPC) is used for the preparation of artificial tears, treat medical conditions characterized by insufficient tear production such as kerotoconjunctivitis sicca, recurrent corneal erosions, decreased corneal sensitivity, exposure, and neuroparalytic keratitis. It is also used as a disintegrant and a binder in tablets, sieving matrix for DNA separations by capillary and microchip electrophoresis and lubricant for artificial eyes, food additive, thickener, and as an emulsion stabilizer [111, 112]. 

Chiral separation of flavonoids has also been carried out by chromatographic systems by using a chemically bonded chiral stationary phase or by the addition of chiral mobile phase additives (reviewed by Yanez et al. ). These chiral polymer phases can be further subdivided into polysaccharide-derived columns, and cyclodextrin and mixed cyclodextrin columns. With regard to chiral mobile phase additives, the addition of an optically active molecule to the mobile phase can facilitate separation of enantiomers on conventional stationary phases. Cyclodextrin as a chiral additive is widely used to separate enantiomers mainly by capillary electrophoresis (CE), as discussed in Section 3.6.2.I. Table 3.7 summarizes the most habitual HPLC procedures employed for the analysis of various classes of food flavonoids. 

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