Parameters extraction, water quality

Mackay, D., Shiu, W.Y., Wolkoff, A.W. (1975) Gas chromatographic determination of low concentrations of hydrocarbons in water by vapor phase extraction. Water Quality Parameters. ASTM STP 573, pp. 251-258, Am. Soc. Testing and Materials, Philadelphia. 

The results of water quality analyses were extracted from the water quality database for the period of January 1, 1994 to December 31, 2006. This resulted in 10,664 usable water chemistry results, although not every parameter was analysed is each case resulting in variations in the sample size. The domestic well log database reported... 

Extraction is the first step of pesticide residue analysis of water samples. Any pesticide residue technique of water samples should include the development of a dependable quantitative extraction procedure. The pitfalls of liquid-liquid extraction as now used are explained. A theoretical approach for quantitation of the extraction step based upon the thermodynamic partition coefficient as a p-value is proposed. The p-value approach is discussed to enable choosing the best solvent, water quality parameters, and solvent water ratios for serial analysis of water samples containing pesticides. 

The eflFects of natural water quality parameters on quantitative liquid-liquid extraction have seemingly been neglected by many workers. The tables in References 12, 13 and 14 indicate that some water... 

Table II. Water Quality Parameters Involved in Quantitative Liquid—Liquid Extraction...

Using the thermodynamic distribution coefficient for the choice of the best LLE parameters for quantitative extraction of pesticides from water is usually not done. The time to determine the distribution coefficient of a pesticide under different water quality conditions and with different solvents has seemed to justify picking these parameters arbitrarily. Then the parameters chosen are tested by fortifying, usually in distilled water. As indicated above, the arbitrary approach does not work well. A systematic procedure based upon the distribution coefficient is strongly suggested to replace the arbitrary approach. In time a Standard Method for choosing the parameters of LLE for quantitative pesticide analysis may evolve from careful comparative study of parameters. 

Fortifying laboratory water samples approaches actually recovering field samples if a pesticide is completely dissolved and not associated with suspended matter and the other water quality characteristics are similar to natural water (pH, T, ionic strength). In another approach natural water characteristics are altered to laboratory fortification specification to obtain maximum efficiency and to be able to standardize extraction procedures. DiflEerent standardization procedures are needed for samples from diflEerent water environments—e.g., a river water with high turbidity, a clear stream, sea water, or organically polluted lake water. Many different water quality parameters (Table II) and solvents (Table I) are possible to standardize and quantitate LLE. The best choice should be defined for each water type. 

Table IV shows that distilled water, filtered and unfiltered river water, used as a drinking water supply, and a polluted creek water have consistent p-values under the set of water quality parameters described. In these p-value determinations the LLE extraction step is isolated when a sample is extracted from a water solution containing a pesticide at a suflBciently high concentration for direct analysis of the solvent or residual water phases (36).

Taheri Shahraiyni, H., 2007, Extraction of water quality parameters using the satellite data and inverse modeling of radiative transfer equation by active learning method, Phd Thesis, Civil. Eng. Dept., Sharif University of Technology, Tehran, Iran, 167 p. (In Persian). 

Processing effects. Citrus oil quality may be affected by certain processing parameters. Some which have been studied include effects of yield from the fruit, the amount of water used during recovery and extraction, storage of fruit prior to processing, blending of fruit varieties, and handling the emulsion or finished oils (12). 

After the pretreatment, the first extract (with hot water) is obtained at the lowest temperature and always exhibits a higher bloom value or gel strength, which is the common parameter to measure gelatine quality [61]. 

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