No abstract

No abstract

In recent years, blood metabolites have been investigated as a tool for monitoring physiological condition in wild or cultured crustaceans exposed to different environmental conditions. Blood protein levels fluctuate with changes in environmental and physiological conditions and play fundamental roles in the physiology of crustaceans from O2transport to reproduction up to stress responses. Proteins are major contributors to hemolymph density, and the present study correlates the easy and low cost measure of hemolymph density by a density-salinity refractometer with the total protein concentration, measured with a colorimetric method. Moreover, the study evaluates the accuracy of the relationship and provides a conversion factor from hemolymph density to protein in seven species of crustaceans, representative of taxa far apart in the phylogenetic tree and characterized by different life habits. Measuring serum-protein concentration by using a refractometer can provide a non-destructive field method to assess crustacean populations/species protein-related modifications of physiological state without need of costly laboratory facilities and procedures.

No abstract

A porous gold electrode supported on one face of an ion-exchange membrane, acting as a solid polymer electrolyte (SPE), is proposed as an amperometric sniffer for monitoring the aldehyde content in the headspace in equilibrium with lipid samples, in order to gain indication of their state of turning rancid It was used as a detector for a flow injection system in which aldehydes were injected, after preconcentration by solid phase microextraction on a SPME fiber from the gas phase standing above thermostated samples and subsequent desorption by heating. Repeatable (AE 4.5%) sharp peaks were detected over a wide linear concentration range (0.5 -200 ppm). A detection limit of about 0.03 ppm was inferred for a signal-to-noise ratio of 3, referred to hexylaldehyde (used as prototype) dissolved in squalene or vegetable oils samples. This approach was applied to the determination of volatile aldehydes from some partially oxidized cereal oils and the results found were compared with both the corresponding peroxide values and their aldehyde content determined by a conventional spectrophotometric method.