Study On Alginate M: G Ratios Determination By High Performance Capillary Electrophoresis

Alginate are negatively charged acidic polysaccharide compounds extracted frombrown algae, widely used in textile, chemical, food, pharmaceutical and otherindustries. M: G ratios represent the relative amount of β-D-Mannuronic Acid (M)and α-L-Guluronic Acid (G). It affects the physical and chemical properties as well asthe application of alginate. M: G ratios are important in alginate product qualitystandard evaluation system and will also be a key point in controlling alginate qualityduring developing its use in high-valued industries.In this study, we selected alginate as the research object, degraded intomonosaccarides with acidic solution. The products were derivatived with1-phenyl-3-methyl-5-pyrazolone (PMP) to get high ultraviolet absorption and studiedthe performance in HPCE using the CZE-UV detection technique, established andoptimized the PMP pre-column derivatization/HPCE method for the determination ofalginate M: G ratios. We studied the degradation forms, TFA degradation conditions,PMP derivative conditions of samples preparation process; we also studied influencesof electrophoretic medium concentration and pH value on alginate monosaccharidePMP derivative products separation; we detected the M: G ratios of alginate sampleswith the new established HPCE method.M: G ratios were studied with HPLC, GC,1H NMR and IR methods. Twomethods including HPLC and GC were applied for the analysis of various sampleswith different pretreatment processes after degradation. The samples were performedthe NMR analysis at44℃after slight degradation. The samples were analyzed withIR technique and the areas of PM and PG characteristic absorption peaks were used tocalculate M: G ratios semi-quantitatively.The newly established HPCE method is simple, rapid and of high separationefficiency, which can play an important role in the study of alginate M: G ratios.These studies are to enrich and develop new methods for the determination of the composition of alginates, and to establish and perfect alginates’ quality standardsystem.