Drinking water preconcentration

Drinking water Preconcentration onto 5 pm C18-silica or 7 pm polystyrene-divinyl benzene copolymer with subsequent backflush onto analytical HPLC column. RP-HPLC/UV (254 mn) 0.03-0.06 pg/L (ppb) 91 ( 10% RSD) at sample volumes up to 300 mL Driss et al. 1993... 

N. Bouaicha, I. Maatouk, G. Vincent and Y. Levi, A colorimetric and fluoro-metric microplate assay for the detection of microcystin-LR in drinking water without preconcentration, Food Chem. Toxicol., 40 (2002) 1677-1683. 

Aluminum is a metal which exists abundantly and widely in the earth and is commonly used in food packaging, antiperspirants, antiacid in digestion remedies, cosmetics and in beverages industries [2]. Aluminum sulfate is the most common aluminum-based coagulant used in purify water in many countries and it is found in most drinking water. WHO guidelines set its permissible level in drinking water at 200 ppb [3]. Upper levels can lead to serious problems such as Alzeheimer s disease. So, optimized preconcentration methods are required for the determination of trace amounts aluminum. 

Drinking water Purge-and-trap preconcentration thermal desorption GC/MS 0.1 pg/L (0.1 ppb, w/v) No data Coleman et al. 1976... 

Drinking water Purge-and-trap preconcentration onto Tenax/ silica/charcoal thermal desorption GC with PID and Hall in series 0.02 pg/L 98 (2.5% RSD) Ho 1989... 

The measurement of very low levels of environmental pollutants is becoming increasingly important. The determination of lead, a cumulative toxin, is a good example. The current maximum allowable concentration of lead in British drinking water, before it enters the distribution network, is SO ng ml [29]. Although electrothermal atomization atomic-absorption spectrometry (AAS) can be used to measure this and lower concentrations, it is slow and requires considerable effort to ensure accurate results. Flames can provide simple and effective atom sources, but, if samples are aspirated directly, do not provide sufficient sensitivity. Thus, if a flame is to be used as the atom source, a preconcentration step is required. 

Drinking water, river water Preconcentration of 2.5 mL water onto C18 extraction disks, rinsing with additional 1 mL and purging disk with gas to remove residual water. Elution with ethyl acetate directly onto GC precolumn with solvent venting. GC/NPD Tap water 20 pg/mL (ppt) river water 20-50 pg/mL >95 (<4% RSD at 200 PPt) Kwakman et al. 1992... 

Driss MR, Hennion M-C, Bouguerra ML. 1993. Determination of carbaryl and some organophosphorus pesticides in drinking water using on-line liquid chromatographic preconcentration techniques. J Chromatogr 639 352-358. 

V Tatarkovicova. Preconcentration of phenmedipham and desmedipham by sorption on separcol Si C18 T for their determination in drinking water by high performance liquid chromatography. Collect Czech Chem Commun 55 2146-2151, 1990. 

Kim and Kim [6] have described an extremely sensitive determination of nitrite in drinking water (tap water and underground water) and environmental samples (rain, lake water, and soil) by ion exclusion chromatography with electrochemical detection. Potential interferences in the determination of nitrite by the standard spectrophotometric method or by the ion exchange chromatographic method with either conductivity or ultraviolet detection were eliminated. The detection limit was 0.1 pg L 1 without preconcentration. 

Manzoori JL, Sorouraddin MH, Shemiran F. 1996. Preconcentration and spectrophotometric determination of chromium(VI) and total chromium in drinking water by the sorption of chromium diphenylcarbazone with surfactant coated alumnia. Anal Lett 29 2007-2014. 

The presence in drinking water of phenol, cresol and various antioxidants (109-113) used for synthetic rubber preservation was tested by SPE with a Cig cartridge followed by RP-HPLC on a Cig column with UVD at 280 nm °. An automatic LC system was devised for determination of trace amounts of phenols in water, based on SPE preconcentration, RP microcolumns, isocratic methanol-water mobile phase and ELD in the autoincrement mode. LOD was 40-600 ngL, for eleven priority phenols . ... 

ICP-MS is very promising in the area of environmental studies. Many elements can be determined directly in drinking water. In waste water analysis sample decomposition by treatment with HNO3-H2O2 is often required and the most frequent isobaric interferences have been described [559]. For seawater analysis, the salt contents makes sample pretreatment necessary, which can be done by chelate extraction. Beauchemin et al. [560] obtained a preconcentration of a factor of 50 by sorption of the trace elements onto an SiC>2 column treated with 8-hydroxyquino-line and determined Ni, Cu, Zn, Mo, Cd, Pb and U in seawater. In river water Na, Mg, K, Ca, Al, V, Cr, Mn, Cu, Zn, Sr, Mo, Sb, Ba and U could be determined directly and Co, Ni, Cd and Pb after the above mentioned preconcentration procedure. For As, preconcentration by evaporation of the sample was sufficient. Isotope dilution delivers the highest accuracy [561] and the procedure has been applied to... 

Liu, Y., Mou, S., and Heberling, S., Determination of trace level bromate and perchlorate in drinking water by ion chromatography with an evaporative preconcentration technique, J. Chromatogr. A, 956, 85-91, 2002. 

Marvin, C. H., Brindle, I. D., Hall, C. D., and Chiba, M., Development of an automated high-performance liquid chromatographic method for the online preconcentration and determination of trace concentrations of pesticides in drinking water, J. Chromatogr., 503, 167-176, 1990. 

ETAAS is a very suitable method for analysis of natural waters especially with low total dissolved solids (river, drinking water). About 20 elements may be determined in such samples and after preconcentration the number of elements increases to about 30. In waters with high total solid content (marine, estuarine waters) directly about ten to 12 elements are determined. Of course after appropriate chemical treatment and preconcentration their number increases significantly. 

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