Gagné, J. Université du Québec à Rimouski, jean-pierre_gagne@uqar.uquebec.ca

 
ON THE IMPORTANCE OF DIFFERENT EXTRACTION PARAMETERS TO RECOVER SEDIMENTARY CHLOROPHYLL A BIOMARKER
 
Actually there is an increased interest to study the sedimentary chloropigments as biomarker to: 1) evaluate the organic matter quality and lability through kinetic studies; 2) determine the intensity of the benthic-pelagic coupling; 3) discuss bioturbation and near bottom transport or resuspension. All these topics require the analysis of chlorophyll a or other pigments that act as a marker. A lot of attention have been devoted to develop a set of standardized conditions to analyse chlorophyll a by spectroscopic, fluorometric or HPLC methods.However, the extraction procedure upstream to the instrumental analysis have not receive as much attention. In this research, we have examined the effects of various conditions of: 1) temperature; 2) grinding; 3) homogeneization; 4) lyophilisation; 5) solvent; 6) mechanical or ultrasonic agitation, and 7) the number of extractions on the recovery efficiency of sedimentary chlorophyll a. More than 20 sample treatments were tested. Our results show the importance to increase the surface of contact between the sediment sample and the solvent in order to minimize the extraction time and to increase the extraction efficiency. Furthermore, the classic solvent acetone-water 90% has proven is efficiency to extract chlorophyll from our sediments. We propose an extraction scheme that provides a sediment sample ready for chlorophyll a instrumental determination in less than 15 minutes.
 
Day: Thursday, Feb. 4
Time: Poster
Location: Sweeney Center
 
Code: SS36TH1100S