Detergents total, determination

An unknown commercial detergent may contain some combination of anionic, nonionic, cationic, and possibly amphoteric surfactants, inorganic builders and fillers as weU as some minor additives. In general, the analytical scheme iacludes separation of nonsurfactant and inorganic components from the total mixture, classification of the surfactants, separation of iadividual surfactants, and quantitative determination (131). 

Environmental water samples to be analyzed for phosphate are not stored in plastic bottles unless kept frozen, because phosphates can be absorbed onto the walls of plastic bottles. Mercuric chloride, used as a preservative and acid (such as the nitric acid suggested for metals above), should not be used unless total phosphorus is determined. All containers used for water samples to be used for phosphate analysis should be acid rinsed, and commercial detergents containing phosphates should not be used to clean sample containers or laboratory glassware. 

The general environmental situation in the coastal regions of the Black Sea is very complicated and is close to critical [3]. The recent decades have witnessed growing pollution of waters with total phosphorus and nitrogen (Danube seaside), petroleum products (nearby Sebastopol and the Georgian coast), detergents and phenols (the southern coast of Crimea), phenols and pesticides (Odessa coast). Here the quality of coastal waters is determined not so much by the source of the pollutants and the width of the continental shelf, but by the nature and intensity of currents in the particular regions. 

The contaminants are of different origin and include buffers, non-volatile salts, detergents and many compounds of unknown origin. ESI can tolerate only low quantities of contaminant ions. These ions can reduce the abundance of the ions from the compound of interest and can even totally suppress them. They also very often result in the formation of adduct ions, further reducing the sensitivity by distribution of the ion current over several species. Furthermore, they may complicate the determination of the molecular mass, or reduce the accuracy of the molecular mass if some adducts are not separated from the ions of the protonated molecule. 

The leakage of 5(6)-carboxyfluorescein was assessed by determining the increase of fluorescence 490 nm 520 nm) observed in the presence of excess detergent. To measure the total fluorescence intensity corresponding to 100% dye release, Triton X-100 (0.1% w/v final) was added to the vesicles. 

The cytochrome c ELISA kit 96-well plate was incubated three times with PBS for 10 min per incubation. To each well was added 32 pL of buffer F containing 20 pg of BSA. HRP-conjugated detection antibody in conjugate diluent free of detergents was added to obtain the desired concentration. Then Bcl-2 family proteins diluted in buffer E were added. The volume of each well was adjusted to 42 pL with buffer E. Mitochondria were diluted into buffer C, and 8 pL (approx 1.8 pg of protein) was added to each well. The plate was floated in a 30°C water bath for the desired time. Then 200 pL of buffer E were added and the wells were washed 5 times with 300 pL per wash of buffer E and 100 pL of color development reagents was added. After 3 min, stop solution was added and absorbance was measured at 450 nm using 540 nm as a reference wavelength. To determine total detectable cytochrome c, Triton X-100 was added to mitochondria to a final concentration of 0.1%. 

---