. "Separation and preconcentration of Cr(VI) as ion associate using solid phase extraction"@en . "[7D420DCCC73C]" . . "Collection of Czechoslovak Chemical Communications" . "A method of separation and preconcentration of Cr(VI) was developed based on sorption on modified silica gel (C18) of an ion associate of Cr(VI) anion with a quaternary base. The study was performed with the following quaternary onium salts: [1-(ethoxycarbonyl)-pentadecyl]trimethylammonium bromide, 1-hexadecylpyridinium chloride, benzyl(dodecyl)dimethylammonium bromide, butyl(triphenyl)phosphonium bromide and tetraphenylarsonium chloride. Benzyl(dodecyl)dimethylammonium bromide was found the optimum ion-pairing reagent. Sample containing Cr(III) and Cr(VI) in the presence of 0.005 mol/l of benzyl(dodecyl)dimethylammonium bromide was pumped with a peristaltic pump through the column containing the sorbent. The optimum pH range 4-5 was maintained with 0.05 mol/l phosphate buffer. Elution was accomplished using 95 vol.% ethanol and the recovery of Cr(VI) was (96 +/- 6)% in the concentration range 0.005-1 mg/l of Cr(VI); even in a tenfold excess of Cr(III) the recovery of Cr(VI) was 99.8% with the relativ"@cs . "Separation and preconcentration of Cr(VI) as ion associate using solid phase extraction"@en . . "Kanick\u00FD, Viktor" . "Otruba, V\u00EDt\u011Bzslav" . . "RIV/00216224:14310/00:00002852" . "1865" . "Separation and preconcentration of Cr(VI) as ion associate using solid phase extraction"@cs . . . "CZ - \u010Cesk\u00E1 republika" . "Pivni\u010Dka, Jan" . . "3"^^ . . "3"^^ . . . . . "10"^^ . "12" . . "14310" . . "A method of separation and preconcentration of Cr(VI) was developed based on sorption on modified silica gel (C18) of an ion associate of Cr(VI) anion with a quaternary base. The study was performed with the following quaternary onium salts: [1-(ethoxycarbonyl)-pentadecyl]trimethylammonium bromide, 1-hexadecylpyridinium chloride, benzyl(dodecyl)dimethylammonium bromide, butyl(triphenyl)phosphonium bromide and tetraphenylarsonium chloride. Benzyl(dodecyl)dimethylammonium bromide was found the optimum ion-pairing reagent. Sample containing Cr(III) and Cr(VI) in the presence of 0.005 mol/l of benzyl(dodecyl)dimethylammonium bromide was pumped with a peristaltic pump through the column containing the sorbent. The optimum pH range 4-5 was maintained with 0.05 mol/l phosphate buffer. Elution was accomplished using 95 vol.% ethanol and the recovery of Cr(VI) was (96 +/- 6)% in the concentration range 0.005-1 mg/l of Cr(VI); even in a tenfold excess of Cr(III) the recovery of Cr(VI) was 99.8% with the relativ" . "0010-0765" . "Hexavalent chromium; solid phase extraction; ion associate; flame emission spectrometry"@en . "726224" . "Separation and preconcentration of Cr(VI) as ion associate using solid phase extraction"@cs . "P(VS97020)" . . "A method of separation and preconcentration of Cr(VI) was developed based on sorption on modified silica gel (C18) of an ion associate of Cr(VI) anion with a quaternary base. The study was performed with the following quaternary onium salts: [1-(ethoxycarbonyl)-pentadecyl]trimethylammonium bromide, 1-hexadecylpyridinium chloride, benzyl(dodecyl)dimethylammonium bromide, butyl(triphenyl)phosphonium bromide and tetraphenylarsonium chloride. Benzyl(dodecyl)dimethylammonium bromide was found the optimum ion-pairing reagent. Sample containing Cr(III) and Cr(VI) in the presence of 0.005 mol/l of benzyl(dodecyl)dimethylammonium bromide was pumped with a peristaltic pump through the column containing the sorbent. The optimum pH range 4-5 was maintained with 0.05 mol/l phosphate buffer. Elution was accomplished using 95 vol.% ethanol and the recovery of Cr(VI) was (96 +/- 6)% in the concentration range 0.005-1 mg/l of Cr(VI); even in a tenfold excess of Cr(III) the recovery of Cr(VI) was 99.8% with the relativ"@en . "Separation and preconcentration of Cr(VI) as ion associate using solid phase extraction" . "65" . . . "Separation and preconcentration of Cr(VI) as ion associate using solid phase extraction" . . "RIV/00216224:14310/00:00002852!RIV08-MSM-14310___" .