BCO-DMO BlogInstrument: Turner Designs Fluorometer -10-AU
The Turner Designs 10-AU Field Fluorometer is used to measure Chlorophyll fluorescence. The 10AU Fluorometer can be set up for continuous-flow monitoring or discrete sample analyses. A variety of compounds can be measured using application-specific optical filters available from the manufacturer. (read more from Turner Designs, turnerdesigns.com, Sunnyvale, CA, USA)
Chlorophyll procedure: after removal from the freezer, the filters were extracted in 10 ml of methanol. The samples were allowed to extract for 24 hours in the refrigerator. Following extraction, samples were centrifuged for 20 minutes to remove debris. The fluorometer (Turner fluorometer model 10-AU-005) was allowed to warm up and stabilize for 30 minutes prior to use. Pure methanol was measured to confirm the zero position. Samples were transferred to 1-cm cells and they were measured directly into the fluorometer (Fo). 100 µl of 0.48N HCl was added to each cell. A second reading was taken from the fluorometer for each cell (Fa). Standardization. The fluorometer was calibrated every year with a commercially available chlorophyll a standard (Σ). The concentration of chlorophyll-an and phaeopigments in the sample were calculated using Yentsh and Menzel (1963) equation, with a specific absorption coefficient of 74.5 (chlorophyll in methanol).
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