Comparison of the performance of the single- and triple-slot air-acetylene burners for atomic absorption spectrometry

The separation of herbicides by micellar electrokinetic capillary chromatography

“…~2 number of methods, particularly spectrophotometric ,3], differential pulse polarographic [4] and gas chromatb~ [5][6][7][8][9][10][11][12][13][14][15][16][17][18], have been reported for the analysis of blC~des. A strong disadvantage of GC methods is that derivatization of the target compounds is necessary before the final measurements.…”

“…Enrichment and clean-up procedures are nearly always necessary in connection with the HPLC analysis of the chlorophenoxy acids in surface water, urine, soil or sediment. Liquid-Liquid extraction [9,29,30], solid-phase extraction [11,22,25,[31][32][33][34] and enrichment on a precolumn [33,25,[35][36][37] or a supported liquid membrane [38][39][40] can be utilized as the sample pretreatment procedure. Recently, a sample pretreatment technique using isotachophoresis as the sample clean-up and enrichment step prior to the LC analysis was developed [41].…”

Determination of dicamba and 2,4-D in water and soil by isotope dilution GC/MS

“…Numerous gas chromatographic methods have been reported for the analysis of dicamba and 2,4-D in water (Olson et al, 1978; Agemian and Chau, 1977;Aly and Faust, 1964; Devine andZweig, 1969) andsoil (Smith, 1972;Renberg, 1974;Kahn, 1975;Gutenmann and Lisk, 1964;Lee and Chau, 1983). Water samples were acidified and extracted with benzene (Olson et al, 1978; Devine and Zweig, 1969), ethyl acetate (Agemian and Chau, 1977), ether-chloroform (1:3) chloride (Agemian and Chau, 1977), etc.…”

“…Numerous gas chromatographic methods have been reported for the analysis of dicamba and 2,4-D in water (Olson et al, 1978; Agemian and Chau, 1977;Aly and Faust, 1964; Devine andZweig, 1969) andsoil (Smith, 1972;Renberg, 1974;Kahn, 1975;Gutenmann and Lisk, 1964;Lee and Chau, 1983). Water samples were acidified and extracted with benzene (Olson et al, 1978; Devine and Zweig, 1969), ethyl acetate (Agemian and Chau, 1977), ether-chloroform (1:3) chloride (Agemian and Chau, 1977), etc. Soil samples were extracted with calcium hydroxide solution (Smith, 1972), 0.2 M NaOH (Renberg, 1974), sulfuric acid-acetone (Kahn, 1974), acetone-phosphoric acid (Gutenmann and Lisk, 1964), and acetone-hexane following acidification (Lee and Chau, 1983).…”

A multiresidue method for the analysis and verification of several herbicides in water

“…Because of the diversity in herbicide products available to farmers for weed and brush control, environmental water samples would be best analyzed for herbicide residues by using a multiresidue procedure. Two multiresidue analytical methods for the determination of herbicide residues at the ppt and ppb levels in water have been published recently, one method for acidic herbicides (Agemian and Chau, 1977) and the other for herbicides with neutral properties (Lee and Chau, 1983). In the study concerning acidic herbicides, both pentafluorobenzyl and 2-chloroethyl esterification procedures were employed to enhance sensitivity to electron-capture detection.…”