Water samples, extraction

Waste water Add stable isotopically labeled analogs of the compounds to 1 L of waste-water sample extract sample at pH 12-13, then at pH <2, with methylene chloride using continuous extraction techniques dry extract over sodium sulfate concentrate add internal standard inject GC/MS 10 pg/L NR EPA 1990b (Method 1625)... 

Successful bioremediation of PAH-contaminated sites is being more frequently defined as achieving a reduction of PAHs to levels governed by the background concentrations (for example, < 2 standard deviations above background levels). Evidence for this reduction is usually offered by analytical chemistry data generated with replicate soil or water samples extracted and analyzed according to standard procedures such as GC-MS (U.S. EPA Method SW-846 8270) or HPLC (U.S. EPA Method SW-846 8310). 

ESD Equilibrium sampling device Use of PDMS membrane that equilibrates with the surrounding water sample Extraction of halogenated compounds from sea and river water samples... 

Bergmann, K. and B. Neidhart. 2001. In situ propylation of ionic organotin and organolead species in water samples—extraction and determination of the resulting tetraorganometallic compounds by gas chromatography-atomic absorption spectrometry. J. Sep. Sci. 24 221-225. 

Determination of the intact CW agents in urine or blood may proceed by the methods commonly applied to water samples. Extraction with an organic solvent and subsequent cleanup with a Florisil column is a well-established procedure. Rather volatile, scheduled compounds can often be successfully recovered and purified from biological materials by means of dynamic headspace stripping and subsequent adsorption on Tenax tubes these tubes are then subjected to GC/MS analysis. 

MeOH followed with water Sample extraction ... 

The XAD-type resins have been used to remove A-nitrosamines from water samples and sewage effluent. The samples are filtered to remove suspended particles and then they are passed through a column at a flow rate between 11 and 15 ml/min. Acetone-DCM or DCM-diethyl ether (75 25) have been used to desorb the organic compounds retained by the XAD resin. After an appropriate concentration, the final solution can be analyzed directly by HPLC or GC. Alternatively, it may be necessary to perform a further clean-up of the extract prior to the analysis. This clean-up will depend largely on the nature of the water samples extracted and on the complexity of the organic materials present in the sample. 

More recently, a micro-LLE method was described. Extraction is performed on 400 ml water samples extracted once with 500 il toluene. Extracts are then analyzed directly, without any further treatment by GC-ECD. ... 

FIGURE 25.12 GC-MS SIM chromatograms with a HP-5 capillary column of pure water sample extracts, (a) blank and (b) spiked with 0.1 /rg/1 of chlorsulfuron and metsulfuron methyl. (From Klaffenbach, P., and Holland, P. T., ]. Agric. Food Chem., 41, 396, 1993. With permission.)... 

A broad range of methods has been used to study gas exchange in natural waters. Most methods require collection of water samples, extraction of the gas of... 

The carbon dioxide (physically) dissolved in water - we denote it as C02 aq) -is in equilibrium with gaseous atmospheric carbon dioxide C02(g). There is no way to separate non-ionic dissolved C02 aq) and H2CO3 therefore, it is often lumped into C02 aq). Analytically, DIC can be measured by acidifying the water sample, extracting the CO2 gas produced and measuring. The marine carbonate system represents the largest carbon pool in the atmosphere, biosphere and ocean, meaning it is of primary importance for the partition of atmospheric excess carbon dioxide produced by human activity. 

If the fatty acids present as fatty acid compounds (soaps) in water are also to be recorded by this method, then the water samples extracted with... 

IOC (1993), Chlorinated biphenyls in open-ocean waters sampling, extraction, clean-up and instrumental determination. Paris UNESCO Tech. Rep. Ser. 25. 

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