On some factors influencing accuracy and precision of Baltic water absorbance measurements

Various factors influencing the quality of UVVIS spectra obtained for sea water (in 100 mm cells) have been tested. The spectrophometer instability and baseline drift introduced absorbance error of ~ 0.0002 and ~ 0.001, respectively. Deviations caused by improper blanks reached 0.005 ab-sorbance units. Standard deviation of absorbance values determined for samples collected in the Gulf of Gdansk during repetitive casts (0.008-0.022) significantly exceeded the detection limit based on variability of the blank sample (0.002).