Carbamates drinking water

The European drinking water guidelines set a maximum admissible concentration of 0.10 pgL for individual pesticides and their related compounds in drinking water. The recommended methods for oxime carbamates and their metabolites in groundwater and surface water are suitable for detection limits below 0.10 pgL. The first method is the HPLC/lluorescence multiresidue method of de Kok et al The second method is an HPLC/MS/MS method of DuPont Crop Protection which is specific for oxamyl and may be applicable for the analysis of other oxime carbamates in heavily polluted waters. 

B92009 Quality Assurance Project Plan for the National Pesticide Survey of Drinking Water Wells Referee Analyses for Analytical Method 2, Organochlorine Pesticides Analytical Method 4, Carbamates Method 5, Methylcarbamates Method 7, Fumigants and Method 9, Nitrate/Nitrite... 

WHO (1993) Guidelines for Drinking-Water Quality, 2nd Ed., Vol. 1, Recommendations, Geneva Zimmermann, F.K. Mohr, A. (1992) Formaldehyde, glyoxal, urethane, methyl carbamate, 2.3-butanedione, 2,3-hexanedione, ethyl acrylate, dibromoacetonitrile and 2-hydroxypropionitrile... 

Glyphosate is a common herbicide that is often monitored in drinking water. Analytical testing is performed by U.S. EPA method 547 using a post-column reaction HPLC system similar to that in carbamate testing (Figure 7.12). 

Multiple development was traditionally performed manually. It consists of repeated developments of a plate in the same direction with the same solvent over the same distance. The result is narrower bands and improved resolution and detection sensitivity. The Rf values become very precise and are adequate enough for identification. A variation of this method is automated multiple development (AMD) and shows promising future. The HPTLC/AMD method was used to monitor phenylureas, carbamates and triazines in drinking water. HPTLC can also be performed using polar modified stationary phases to separate pesticides in various foodstuffs such as triazines in corn, asparagus, tomatoes, grapes and potatoes [14]. 

High performance thin-layer chromatography (HPTLC) has also been used for the determination of carbamate pesticides.Thus, TLC methods provide increased selectivity through silica derivatization, as well as higher analytical precision and sensitivity with high-performance plates. Butz and Stan reported an HPTLC system with automated multiple development (AMD-HPTLC) to screen water samples for pesticides. The method was applied to the determination of 265 pesticides in drinking water spiked with 100 ng/1 of each analyte. 

Carbamate pesticides can be monitored in die UV at 220 nm, by postcolumn derivatization with o-phdialaldehyde and fluorescence detection, or by thomospray MS [198]. Following US EPA Methods 531.1 and 531.5 for drinking water (C g column with A = 330 nm, ex 465 nm, em and a 30-min 0/100 — 0/100 methanol/ water gradient), baseline separation of 12 V-methyl and W-methyloxime carbamates and selected oxidation products was achieved with detection limits of <0.6 ppb [199]. 

Gaseous CO2 is extensively used to carbonate soft drinks and this use alone accounts for 20% of production. Other quasi-chemical applications are its use as a gas purge, as an inert protective gas for welding, and for the neutralization of caustic and alkaline waste waters. Small amounts are also used in the manufacture of sodium salicylate, basic lead carbonate ( white lead ), and various carbonates such as M2CO3 and M HC03 (M = Na, K, NH4, etc.). One of the most important uses of CO2 is to manufacture urea via ammonium carbamate ... 

Suggest suitable procedures for the SPE of (a) organochlorine pesticides from drinking and surface waters, (b) carbamate pesticides from river water, and (c) acid herbicides from surface water. 

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