APCI groundwater

Crescenzi et al. developed a multi-residue method for pesticides including propanil in drinking water, river water and groundwater based on SPE and LC/MS detection. The recoveries of the pesticides by this method were >80%. Santos etal. developed an on-line SPE method followed by LC/PAD and LC/MS detection in a simultaneous method for anilides and two degradation products (4-chloro-2-methylphenol and 2,4-dichlorophenol) of acidic herbicides in estuarine water samples. To determine the major degradation product of propanil, 3,4-dichloroaniline, the positive ion mode is needed for atmospheric pressure chemical ionization mass spectrometry (APCI/MS) detection. The LOD of 3,4-dichloroaniline by APCI/MS was 0.1-0.02 ng mL for 50-mL water samples. 

Liquid chromatography-APCI-MS with NI and PI was used for the trace determination of several OPPs in groundwater. The limit of quantification varied between 5 and 37 ng/L in PI. Under the NI mode of operation, only the parathion group (both parathions and fenitrothion) had a better sensitivity than with the PI mode, with quantitation limit of 5-15 ng/L, whereas the rest of the pesticides had 2-4 times higher limits as compared to those in PI mode (52). 

Spliid and Kpppen described a method using LLE and LC-APCI-MS for the analysis of water. The method proposed was then used to investigate the contamination of Danish ground-water with pesticides. More than 200 samples of groundwater collected from various areas of the country were analyzed. Metramitron was detected one or more times in concentrations ranging from the detection limit level to 19 /rg/L (32). 

The use of APCI for the analysis of drugs or their metabolites in environmental samples is not yet as common as for ESI applications (cf 15.3.3.2 ESI, dmgs). Predominantly aqueous samples, e.g., effluents of STPs or wastewaters from pharmaceutical industry were studied. Surface and groundwater samples were also under... 

An APCI-LC-MS method was developed and described for the quantitative determination of the anilide pesticides alachlor and metazachlor in ground water samples. After optimization of instrumental conditions detection limits of 0.001-0.005 pg L (50-300 pg injected) could be obtained. Recovery, precision and linearity data were reported [350]. The pesticide bentazone was one of the most frequently found compounds determined by APCI-LC-MS in shallow groundwater samples from twosandy and two clay catchment areas [351]. 

The urea pesticides diuron, fluormeturon, neburon and Hnuron cited as potential groundwater contaminants from US EPA in the National Pesticide Survey were quantitatively determined by APCI-LC-MS(-t) [354]. APCI-LC-MS was also used to test for 46 pesticide compounds in shallow groundwater samples from two sandy and two clay catchment areas. Of the neutral polars observed, isopro-turon belonged to the most frequently found compound [351]. Sphid et al. described an APCI-LC-MS method for the determination of isoproturon and different types of pesticides and their degradation products in ground water samples. Detection Umits, recovery, precision and Hnearity data were reported [350]. 

Since triazines are very mobile in the aquatic environment, the presence of these pesticide types in groundwater samples could be confirmed. Pollution was observed when neutral pesticides contained in shallow groundwater samples from two sandy and two clay catchment areas were analysed in APCI mode [351]. The most frequently (> 300 samples) determined compound was atrazine with its degradation products. 

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