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Spectrophotometric studies of marine surfactants in the southern Baltic Sea

Drozdowska V., Józefowicz M.

Oceanologia

2015

No. 57 (2)

159--167

It is well known that surfactants in the southern Baltic Sea constitute the organic matter from riverine waters discharges as well as the secondary degradation products of marine phytoplankton excretion. They reach the surface microlayer by the upwellings and turbulent motions of water and in the membranes of the vesicles as well as from the atmosphere. To assess concentration and spatial distribution of marine surfactants in the southern Baltic Sea, the steady-state spectrophotometric and spectrofluorometric measurements of water samples taken from a surface film and a depth of 0.5 m were carried out. Water samples were collected during windless days of the cruise of r/v ‘Oceania’ in November 2012, from the open and the coastal waters having regard to the vicinity of the Vistula and Łeba mouths. In the present paper, fractions of dissolved organic matter having chromophores (CDOM) or fluorophores (FDOM) are recognized through their specific spectroscopic behavior, i.e., steady-state absorption, fluorescence excitation and fluorescence spectra. The steady-state spectroscopic measurements revealed the CDOM and FDOM molecules characteristic to both the land and marine origin. Moreover, the concentration and spatial distribution of marine surfactants significantly depend on the distance from the river mouth. Finally, higher values of absorbance and fluorescence intensity observed in a surface film in comparison to these values in a depth of 0.5 m clearly suggest the higher concentration of organic matter in a marine film. On the other hand, our results revealed that a surface microlayer is composed of the same CDOM and FDOM as bulk water.

Fluorescence determination of hemoglobin based on its enzymatic activity

Xu C., Li B., Zhang Z.

Chemia Analityczna

2002

Vol. 47, No. 6

895-903

A novel fluorescence system for determination of hemoglobin (Hb) is presented. It is based on the Hb-catalyzed oxidation of nonfluoroscent thiamine to fluorescent thiochrome by H(2)O(2) in basic medium. The enzymatic reaction at room temperature was studied by measuring the increase in fluorescence intensity of thiochrome at 440 nm in order to obtain the initial reaction rate. The initial reaction rate was linear with Hb concentration in the range of l.0 x 10(-7)-2.0 x 10(-10) mol L(-1) and the limit of detection was 4.6 x 10(-11) mol L(-1). The method is simple, sensitive and reliable for the determination of Hb and has been successfully applied to the determination of Hb in human urine.

Przedstawiono nową, fluorescencyjną metodę oznaczania hemoglobiny (Hb). Podstawą metody jest reakcja utleniania tiaminy (nie wykazującej fluorescencji) do tiochromu (wykazującego fluorescencję). Reakcja ta, zachodząca pod wpływem H(2)O(2) w środowisku alkalicznym, jest enzymatycznie katalizowana przez Hb. W celu wyznaczenia początkowej szybkości reakcji badano ją w temperaturze pokojowej mierząc wzrost natężenia fluorescencji tiochromu przy długości fali 440 nm. Początkowa szybkość reakcji rosła ze wzrostem stężenia Hb w zakresie l x 10(-7)-2 x 10(-10) mol L(-1), a granica detekcji wynosiła 4.6 x 10(-11) mol L(-1). Opracowana metoda oznaczania Hb jest prosta, czuła i wiarygodna. Zastosowano jaz powodzeniem do oznaczania Hb w moczu ludzkim.