Molecular species analysis of monosialogangliosides from sea urchin Strongylocentrotus nudus by RPLC-ESI-MS/MS.

Sea urchin gangliosides have been proved to contain neuritogenic activities, which related to their molecular compositions. This study reports a method utilizing reversed-phase chromatography coupled to mass spectrometry for structure investigation and molecular species determination of the monosialogangliosides from sea urchin Strongylocentrotus nudus. Two types of sulfated and nonsulfated monosialogangliosides were isolated from the sea urchin ovary. In MS(2) spectra of both nonsulfated monosialoganglioside and sulfated monosialoganglioside, 2-6 linked sialic acids were identified by the characteristic fragments of (0,4)A2-CO2 and (0,2)A1. Fragment ions at m/z 139.1 and m/z 169.1 of nonsulfated monosialoganglioside might be characteristic for 8-sulfated sialic acid residue. Retention time of the molecules was effectively used in the characterization of unknown molecules, and molecules that differ in mass by only 0.04 Da were easily differentiated.

Innovative method for determining glycogen content in the Pacific oyster (Crassostrea gigas) by ion chromatography.

A precise analytical assay was developed and validated for the determination of Pacific oyster glycogen using ion chromatography. The Pacific oyster glycogen was quantified by the determination of glucose-6-phosphate (Glc-6-P), which was derived from glucose that was hydrolyzed from glycogen. Glc-6-P, adenosine triphosphate, and adenosine diphosphate were separated by ion chromatography. The method was validated over the curve range 0.5-100mg/L for the abovementioned analytes. The recoveries were between 95% and 102%. The relative standard deviations (RSDs, c=10mg/L, n=9) were less than 4.37%. Unlike a traditional method, this validated method was inexpensive and stable.

Determination of biogenic amines in squid and white prawn by high-performance liquid chromatography with postcolumn derivatization.

A simple method was developed for the determination of biogenic amines in aquatic food products using a reverse-phase high-performance liquid chromatography with postcolumn automatic o-phthalaldehyde derivatization and fluorescence detection. The linearity, repeatability, and recovery of the method for seven amines (tyramine, putrescine, cadaverine, histamine, agmatine, spermidine, and spermine) were evaluated. This optimized method was applied to detect biogenic amines in squid and white prawn during refrigerated storage. Sensory analysis, pH value, and total volatile base nitrogen value were combined to evaluate the freshness quality of these two raw materials. Agmatine and cadaverine in squid, cadaverine, and putrescine in white prawn were the most obviously changed amines during the storage at two different temperatures, and these biogenic amines could be the effective quality indicators for the freshness of the raw aquatic materials.

Determination of the big head carp myofibrillar (Aristichthys nobilis) adenosine triphosphatase activity by ion chromatography.

A method for the determination of adenosine triphosphatase (ATPase) activity of myofibrils of big head carp by using ion chromatography was introduced. Adenosine triphosphate (ATP), adenosine diphosphate (ADP) and orthophosphate (Pi) were separated completely. Recoveries for ATP, ADP and Pi were 98+/-5%, 97+/-4% and 98+/-5%, respectively. Pi liberated from ATP during reaction was monitored by ion chromatography using the suggested method. This method was applicable to the determination of myofibrils ATPase activity for quick quality evaluation of surimi.