Vitamins, analysis

Watanabe, F. and Miyamoto, E., Hydrophilic vitamins, analysis by TEC, in Encyclopedia Chromatography, Gazes, J., Ed., Marcel Dekker, New York, 2004 (online version). 

A glance at vitamins in clinical medicine opens a wide panorama with challenging aspects in hepatic conditions, in oxalosis and calculus disease, in obscure, but widely spread neurological diseases, and in many others astute clinical observations, combined with knowledge of the function and mechanism of vitamin action, will bring vitamin analysis into the picture as a useful tool. 

C. Turner, J.W. King and L. Mathiasson, Supercritical fluid extraction and chromatography for fat-soluble vitamin analysis. J. ChromatogrA 936 (2001) 215-237. 

Vitamin Analysis Kit solution for the determination of vitamins and aromatic molecules... 

Vitamins are generally labile compounds and many of them are susceptible to oxidation and breakdown. Since the mid-1970s, the most applied method for vitamins analysis has been HPLC, because this technique does not need hard derivatization and its nondestructive nature allows the use of HPLC both as a preparative purification method as well as for quantification. 

Many reviews [404-406] and book chapters [407-409] have been published on vitamins analysis by HPLC. The aim of this chapter is not to be an exhaustive review of vitamin analyses, but just an overview of the possible applications of HPLC in this field. The attention has been focused on studies done in the last 10 years. 

Retinoids The challenge in fat-soluble vitamins analysis is to separate them from the lipid fraction that contains interferents. Alkaline hydrolysis, followed by LLE, is widely applied to remove triglycerides. This technique converts the vitamin A ester to all-trani-retinol. A milder process, which does not hydrolyze vitamin A ester, is alcoholysis carried out with metha-nolic KOH solution under specific conditions that favor alcoholysis rather than saponification. A more accurate explanation of this technique is reported in the book Food Analysis by FIPLC [409]. For some kind of matrices a simple liquid extraction can be sufficient with [421-423] or without [424,425] the purification... 

R. Eitenmiller and W. Landen, Vitamin Analysis for the Health and Food Sciences (1998), CRC Press (Boca Raton, FL). Review of vitamin measurement. 

T Devlin, Editor, Textbook of Biochemistry with Clinical Correlations, 4th ed (1997), John Wiley Sons (New York), pp 1127, 1098 Vitamin C and cholesterol R Eitenmiller and W Landen, Vitamin Analysis for the Health and Food Sciences (1998), CRC Press (Boca Raton, FL) Review of vitamin measurement R Garrett and C Grisham, Biochemistry, 2nd ed (1999), W B Saunders (Orlando, FL), pp 599-600, 840-846 An introduction to vitamin C and cholesterol B Halhwell, Trends Biochem. Sci. 24, 255-259 (1999) Vitamin C Poison, Prophylactic or Panacea5 ... 

HPLC instrumentation and column technology have undergone major advances since the early 1970s, when HPLC made its debut in the field of vitamin analysis. Yet sample preparation in food analysis continues to rely largely on manual wet-chemical techniques, which are time consuming and labor intensive, require considerable analytical skill, and constitute the major source of error in the assay procedure. There is also the serious problem of environmental pollution and the exposure of laboratory personnel to toxic chemicals. 

In general, it is very difficult reliably to extract and quantitate multiple vitamins from complex food systems, due to their diverse physical and chemical properties. Consequently, the extraction of the vitamins from the food matrix is usually the greatest challenge of vitamin analysis. This is especially true for the naturally occurring vitamins, which are often bound to other food constituents, such as carbohydrates or proteins. To prevent vitamin degradation or loss, the extraction conditions should complement the labile nature of the vitamins. Indiscriminate mixing and matching of extraction and quantitation methods is not recommended, since the extraction conditions can affect subsequent separation and quantitation steps. 

PM Finglas, U Faure, PJ Wagstaffe. Improvements in the determination of vitamins in food through intercomparisons and preparation of RMs for vitamin analysis within the BCR programme. Fresenius J Anal Chem 345 180-184, 1993. 

In general, antioxidants are divided into natural and synthetic groups. Because natural antioxidants are discussed in other chapters ( The Fat-soluble Vitamins, Analysis of Phenolic Compounds, and Analysis of Organic Acids ), we deal here only with the determination of synthetic phenolic antioxidants (SPA). 

Lumley, I.D. (1993) Vitamin analysis in foods in The Technology of Vitamins in Food (ed. P. Berry Ottaway), by Blackie Academic Professional, Glasgow, Scotland. 

Many of the methods that have been devised for vitamin analysis are now of little more than historical interest, and, in general, unless there is some reason. 

Table 6.5. Summary of Analytical Method Performance Parameters for Vitamin Analysis...

Schiewe, J., Mrestani, Y., and Neubert, R., Application and optimization of capillary zone electrophoresis in vitamin analysis, J. Chromatogr. A, 717, 255, 1995. 

Research into new analytical techniques for foodstuffs continues, striving for greater accuracy, sensitivity or simplicity, for more rapid methods, for simultaneous multielement analysis, etc. Chromatographic techniques, e.g., LC, GLC, GC-MS, have led to great improvements in the levels of accuracy, sensitivity, and detection that can be achieved for many analytes including carbohydrates, certain vitamins, chemical residues, and additives. Work is still required, for instance, in the area of vitamin analysis in order to provide standard techniques that are applicable to all food types and that would enable concurrent multi-vitamin analysis to take place. Many of the microbiological assays currently used for vitamin determination involve long incubation times and more rapid techniques are needed. 

At present, much effort is being devoted to simultaneous separation and detection of water-soluble vitamins. Undoubtedly, multiple water-vitamin analysis using LC as a separation method is effective with RP ion pair chromatography with acidified methanol or acetonitrile water as the mobile phase. Detection is performed using combined systems such as UV absorbance and fluorescence systems, depending on the vitamins to be determined. Analysis in real food... 

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