Sugar analysis, quantitative

ANALYTICAL METHOD FOR SUGAR ANALYSIS 10.10.1 Quantitative Analysis... 

Recoveries also depend on the wine matrix white and red wines differ for volatiles and polyphenols, and contents of alcohol and sugars. For quantitative analysis, internal standards have to be spiked to the sample in suitable concentration, such as dimethyl sulfide-d6 (d6-DMS) 25 pg/L, dipropyl disulfide (DPDS) 25 pg/L, 4-methylthiazole (MT) lOpg/L, and 3-(methylthio)-l-hexanol (MTH) 50pg/L. A white wine matrix can be used [e.g., 10% v/v ethanol, sugar content <4g/L, and a polyphenolic content of 115mg/L expressed as (+)-catechin] for preparation of standard solutions to calculate the calibration curve for analytes, containing total S02 corrected to 100 g/L and previously treated twice with charcoal 3 g/L to remove sulfur and less polar volatile compounds (higher alcohols are not removed). 

Gas chromatography This was the first quantitative chromatographic system for sugars analysis, but it has been replaced by liquid chromatographic methods, which are simpler, less expensive, and require no derivatization, except in the fermentation industries, where the ease of analysis of alcohols and other fermentation products along with starting (glucose. 

The biosynthesis of amino-sugars and their incorporation into polysaccharides and glycoproteins have been studied in a number of species of fungi. Levels of amino-sugars were quantitated after hydrolysis, using an automated amino-add analyser, programmed for the separation of amino-sugars, or by g.l.c. analysis. 

With the advent of new, more versatile and more robust LC-MS interfaces based on atmospheric-pressure ionization, the use of thermospray will rapidly diminish. However, the above-mentioned applications in sugar analysis as well as a large number of other applications in organic ion analysis such as phenoxy-acetic acids [128], quaternary ammonium pesticides [129, 130], anionic surfactants [131, 132], sulfated azo dyes [133, 134], sulfonamides [135], and ff-lactam antibiotics [136, 137] have proved the potential of this coupling technique in qualitative and quantitative analysis. 

Quantitative Sugar Analysis, Including Sialic Acid (Chambers and Clamp 1971, Clamp et al 1971, Kamerling et al 1975 a)... 

The quantitative sugar analysis is carried out on a CPsil5 WCOT fused silica capillary column (25 mx 0.32mm, i.d.) using flame-ionization detection. The carrier gas nitrogen flow-rate is 1.5 ml/min and the make-up gas nitrogen flow-rate 35ml/min. The split-ratio amounts 1 10. The injection-port temperature is 210 °C, and the detector temperature 230 X. The oven temperature is... 

Pukl, M. and Prosek, M. (1990). Rapid quantitative TLC analysis of sugars using an improved commonly used solvent system. /. Planar Chromatogr. 3,173-176. 

Recent applications of HPAEC-PAD are many and varied. A representative list includes quantitation of polyglucose metabolites in plasma of dialysis patients,148 analysis of heat-treated milk,149 carbohydrate content in lipopolysaccharides,150 phosphorylated sugars in tissue samples,151 composition of soybean meal,152 carbohydrate composition of recombinant modified tissue plasminogen activator,153 analysis of cyclization products from an enzyme reaction,154 carbohydrate content of glycoconjugate vaccines,155 and monitoring of patients with rheumatoid arthritis.156... 

One special feature in the interpretation of the quantitative results seems not to have been exploited in practical analysis, and it certainly deserves attention. The result of the methylation analysis is sometimes complex, and can reveal the occurrence of 10 to 20 different methylated sugars. In this situation, it is not easy to decide, by simple inspection of the analytical data, whether the result could be caused by one complex, carbohydrate chain, or by a structure containing several saccharide chains bound to a common aglycon. In addition, it is not always easy to decide whether the result could fit any natural structure, or mixture of structures, or whether the complex result is attributable to undermethylation. 

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