High-speed separation of carboxylic acids by co-electroosmotic capillary electrophoresis with direct and indirect UV detection

Volgger, Dietmar; Zemann, Andreas; Bonn, Günther K.; Antal, Michael Jerry

doi:10.1016/s0021-9673(96)00744-3

Cited by 70 publications

(43 citation statements)

References 50 publications

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“…[17][18][19][20] It is generally conducted under inverse polarity and reversed electroosmotic flow. [19][20][21] It is also possible to carry out anion separations without flow reversal, even though this last approach often leads to longer analysis time. 17,22 Figure 2 presents an analysis of a crude batch of terephthalic acid in both normal and reversed flow conditions.…”

Section: Resultsmentioning

confidence: 99%

Analysis of impurities in crude and highly-purified terephthalic acid by capillary electrophoresis

Moraes¹,

Rubim²,

Realpozo³

et al. 2004

J. Braz. Chem. Soc.

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Neste trabalho, foi desenvolvido um método simples e rápido, utilizando eletroforese capilar (CE), para a análise simultânea de 4-carboxibenzaldeído (4-CBA), ácido p-toluóico (pTOL) e ácido benzóico (BZ), em lotes industriais de ácido tereftálico cru (CTA) e purificado (PTA). As condições eletroforéticas de análise foram: tampão tetraborato a 20 mmol L -1 (pH 9), injeção hidrodinâmica (5 s, 17 kPa), tensão aplicada de +30 kV e detecção direta em 200 nm.Foram analisados cinco lotes de CTA e quatro lotes de PTA nos teores de 4-CBA e pTOL pela metodologia proposta e as metodologias utilizadas na empresa Tereftalatos Mexicanos S.A. (TEMEX), que são cromatografia gasosa para pTOL e polarografia para 4-CBA, mostrando concordância entre os valores encontrados. Os níveis de BZ foram determinados apenas pela metodologia CE, apresentando no CTA, valores compreendidos entre 60 e 300 ppm, enquanto que no PTA, 5 a 7 ppm. Várias impurezas derivadas da oxidação incompleta do p-xileno foram investigadas, constatando-se a presença do ácido 4-hidroximetilbenzóico por comparação com padrões.In this work, a simple and fast capillary electrophoresis method for the simultaneous analysis of 4-carboxybenzaldehyde (4-CBA), p-toluic acid (pTOL) and benzoic acid (BZ) in industrial batches of crude (CTA) and highly-purified (PTA) terephthalic acid was developed. The electrophoretic conditions comprise: 20 mmol L -1 tetraborate buffer at pH 9, hydrodynamic injection (5 s/17 kPa), applied voltage of +30 kV and direct UV detection at 200 nm.The concentrations of 4-CBA and pTOL in five batches of CTA and four batches of PTA as determined by the proposed CE methodology were in agreement with the results from gas chromatography and polarography methods in current use in Tereftalatos Mexicanos S.A. (TEMEX). Levels of BZ were determined only by the CE methodology and ranged from 60 -300 ppm in CTA and 5 -7 ppm in PTA. Several impurities deriving from the incomplete oxidation of p-xylene were investigated. So far the positive identification of 4-hydroxymethylbenzoic acid was accomplished by comparison with pure standards.

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Section: Resultsmentioning

confidence: 99%

Analysis of impurities in crude and highly-purified terephthalic acid by capillary electrophoresis

Moraes¹,

Rubim²,

Realpozo³

et al. 2004

J. Braz. Chem. Soc.

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“…The content of organic modifiers must be about 40 vol-%, but the kind of organic modifier is not critical [20]. Under optimized conditions, the chloro-substituted phenols can be separated according to their dissociation constants (pK a ) in less than 14 min.…”

Section: Resultsmentioning

confidence: 99%

Separation of Chlorophenols by Capillary Zone Electrophoresis. The Influence of pH of the Electrophoretic Buffer on Selectivity

Liu

Frank

1998

J. High Resol. Chromatogr.

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“…5 reached completion within 2 days and did not seem to exhibit any product degradation as the conjugate peak \vas not observed to deteriorate with time.…”

Section: And Is Presented Dong Withmentioning

confidence: 99%

“…Howeva, the reaction occuned too rapidly at pH 10. 5 to be monitored with any procision. Therefore, the pK range of 7.5-10 was saidiedLinearly regressed plots of In (FITC peak area) venus derivatization time provided correlation coefficients that were usually 0.960.97 (r value).…”

Section: Methdlogymentioning

confidence: 99%

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Single-label fluorescent derivatization of peptides

Little

Paquette

Harvey

et al. 1997

Analytica Chimica Acta

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High-speed separation of carboxylic acids by co-electroosmotic capillary electrophoresis with direct and indirect UV detection

Cited by 70 publications

References 50 publications

Analysis of impurities in crude and highly-purified terephthalic acid by capillary electrophoresis

Analysis of impurities in crude and highly-purified terephthalic acid by capillary electrophoresis

Separation of Chlorophenols by Capillary Zone Electrophoresis. The Influence of pH of the Electrophoretic Buffer on Selectivity

Single-label fluorescent derivatization of peptides

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