A review of reaction detection in HPLC

Brinkman, U.A.Th.

doi:10.1007/bf02688480

Cited by 65 publications

(10 citation statements)

References 59 publications

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“…Os benefícios dessa técnica são: a possibilidade de evitar a interferência de artefatos, usualmente observados em reações comuns de derivação; a alta reprodutibilidade, mesmo no caso da incompleta conversão pela enzima ou da instabilidade do produto de reação. 90 As desvantagens são geralmente devidas ao alargamento da banda cromatográfica e aos efeitos de diluição de reagentes eventualmente adicionados; à necessidade de, algumas vezes, aumentar a sensibilidade do método analítico pela derivação do produto; à necessidade de modificar as condições experimentais utilizadas na etapa de separação, que são diferentes daquelas necessárias para que ocorra a reação enzimática como, por exemplo, mudança no valor de pH, troca dos solventes orgânicos ou alteração na temperatura. 91 Quando possível, o uso do IMER, como pós-coluna analítica, se torna uma boa escolha uma vez que pode ser conectado diretamente a detectores específicos e não há necessidade de sucessivas etapas de separação.…”

Section: Configurações De Imers Em Estudos On-lineunclassified

Imobilização de enzimas em suportes cromatográficos: uma ferramenta na busca por substâncias bioativas

Cardoso¹,

Moraes²,

Cass³

2009

Quím. Nova

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Recebido em 5/10/07; aceito em 11/7/08; publicado na web em 2/12/08 IMMOBILIZATION OF THE ENZYMES ON CHROMATOGRAPHIC SUPPORTS: A TOOL TO RESEARCH OF INHIBITOR COMPOUNDS. The development and characterization of bioreactors or IMER (immobilized enzyme reactors) as research tools are important in the scope of medicinal chemistry and constitute an alternative for the rational development of drugs. This approach does not require highly purified enzymes or a great amount of protein, but increase the enzymatic stability against heat, organic solvents and pH, without too much loss of catalyst activity. Immobilized enzyme reactors (IMER) can be used for the accomplishment of high efficiency screening on-line and, thus inhibitors can be quickly identified. Here, we emphasize the development of IMER by use of different methods of immobilization and chromatographic supports. Their applications, in different areas of research, are also fully discussed.

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Section: Configurações De Imers Em Estudos On-lineunclassified

Imobilização de enzimas em suportes cromatográficos: uma ferramenta na busca por substâncias bioativas

Cardoso¹,

Moraes²,

Cass³

2009

Quím. Nova

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“…Non‐enzymatic Techniques. There are only a few examples for the application of HPLC systems to the on‐line glucose monitoring (Brinkmann, 1987; Gregory et al, 1994; Ohara et al, 1993; van de Merbel et al, 1993, 1994). Recently, van de Merbel et al (1993, 1994) have used this method for the monitoring of E. coli , A. niger , and yeast cultures.…”

Section: Techniques For Glucose Monitoringmentioning

confidence: 99%

Control of Long-Term Perfusion Chinese Hamster Ovary Cell Culture by Glucose Auxostat

Konstantinov

Tsai

Moles³

et al. 1996

Biotechnol. Prog.

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The strategies for control of the feed rate in high-density perfusion cultures of animal cells are limited to several simple schemes. While in an industrial environment simplicity is seen as a major advantage, the need for more elaborate closed-loop control methods that can improve process stability in long-term continuous cultures is also well understood. What has prevented the application of the advanced control strategies known from theory is the lack of reliable real-time information that can be used to close the feedback loop. Among the variables that are appropriate for direct feedback control of the perfusion rate, high priority should be given to the glucose concentration. Unlike some other environmental variables, such as dissolved oxygen and pH, it provides unambiguous information which facilitates the selection of the right feed rate. The present paper describes the application of a closed loop control scheme, known as a "glucose-stat", to the long-term cultivation of Chinese hamster ovary cells in a high-density (35-40 million cells/mL) perfusion process. The monitoring and control system worked successfully for more than 2.5 months without any signs of performance degradation. In targeting industrial application, issues such as reliability, sterility, and accuracy, are given high priority. The implementation of the glucose monitoring system, which is the main part of the control complex, is addressed in details. The performance of the perfusion culture was evaluated at four different glucose set points, providing essential information about process optimization. It became evident that the perfusion culture was operated in the so-called "high-gain" zone (where the system is highly sensitive to the dilution rate), which justifies the application of a feedback control. The on-line glucose concentration was also used by an embedded expert system which drove the process through the batch and the perfusion phase, achieving total computer control of the feed rate. In summary, the proposed glucose monitoring and control technique proved to be a reliable biotechnology tool which can be applied with confidence at an industrial scale to either microbial or mammalian cell cultures.

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“…In some cases derivatization can be carried out on-line before (pre-column) or after the separation column (post-column) [23]. In some cases derivatization can be carried out on-line before (pre-column) or after the separation column (post-column) [23].…”

Section: Detector Selectivity For Selected Compoundsmentioning

confidence: 99%

Chemical Sensors and Instrumentation in Analytical Chemistry

Oehme

1991

Sensors

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A review of reaction detection in HPLC

Cited by 65 publications

References 59 publications

Imobilização de enzimas em suportes cromatográficos: uma ferramenta na busca por substâncias bioativas

Imobilização de enzimas em suportes cromatográficos: uma ferramenta na busca por substâncias bioativas

Control of Long-Term Perfusion Chinese Hamster Ovary Cell Culture by Glucose Auxostat

Chemical Sensors and Instrumentation in Analytical Chemistry

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