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

 
A RAPID METHOD FOR DETERMINING DISSOLVED ORGANIC CARBON IN MARINE SEDIMENT PORE WATERS USING NANOLITER SAMPLE VOLUMES
 
We have developed a simple flow injection technique to analyze dissolved organic carbon (DOC) in nanoliter (nL) sample volumes (10-9 liters) of sediment pore water. Between 60 to 500 nL of interstitial water were introduced with a loop injector directly into a capillary tube connected to a scanning UV-VIS detector. A nanocell detection device (30 nL volume) allowed the acquisition of an UV-VIS spectrum or a specific wavelength signal. We have found a close correlation between the UV absorbance at 254 nm and the DOC concentration. No salt effect has been observed. The analysis was completed in less than two minutes. Easy to set up and physically robust, this system can be readily used on shipboard with a throughput of 30 samples per hour. The UV method compared successfully with the high-temperature catalytic oxidation (HTCO) method. We have applied the method to determine the microscale distribution (2 mm scale) of DOC in interstitial water, and to study the diagenetic evolution of DOC in Saguenay fjord (Quebec, Canada) sediment following an important flood event in July 1996.
 
Day: Tuesday, Feb. 2
Time:
Location: Sweeney Center
 
Code: SS34TU0077S