A new form of chromatogram employing two liquid phases

Martin, A. J. P.; Synge, R. L. M.

doi:10.1042/bj0351358

Cited by 1,505 publications

(362 citation statements)

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“…Therefore, knowledge of factors affecting band broadening is essential in chromatographic separation. Two widely accepted models for describing band broadening are the plate [1] and the rate theories [2,3]. The plate theory has been suggested to lack reality [4] because the carrier gas flow in the column is obviously continuous.…”

Section: Generalmentioning

confidence: 99%

“…Thus, the expanded Eq. (2) is an alternative approach for analysis of w b from the thermodynamic and kinetic energies, which is very different to the two widely accepted plate theory of Martin and Synge [1] and rate theory of van Deemter et al [2] and Golay [3]. It may help in tailoring the stationary phase into a sharper peak and improve overall column performance.…”

Section: Prediction Of Peak Widths Of N-alkanes Eluted From Capillarymentioning

confidence: 99%

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Prediction of gas chromatographic peak width in capillary columns at different temperatures, carrier gas flows, column lengths, inside diameters and carbon numbers

Krisnangkura

Pongtonkulpanich

2006

J of Separation Science

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Original PaperPrediction of gas chromatographic peak width in capillary columns at different temperatures, carrier gas flows, column lengths, inside diameters and carbon numbersWidth factor (w f ), relative band broadening (b r ) and retention factor are linearly correlated as ln w f = lnb r + lnk [Chromatographia (2002) 56, 99 -103]. The k and b r are thermodynamic and kinetic energy parameters, and expanded to cover volumetric flow of carrier gas, temperature, phase ratio (b) and carbon number (z). For columns of the same stationary phase and b value but of different lengths, width at base (w b ) can be predicted with the same numerical values of the constants. The average absolute differences between predicted and experimental w b for BP-1 columns of 30, 20 and 10 m are 1.27%, 1.21% and 1.37%, respectively. In predicting w b of n-alkanes eluted from columns of the same stationary phase but of different ID, only the differences of ln b are required for adjustment of one of the numerical values. The average absolute differences between w b (cal) and w b (exp) values for columns of 0.53, 0.32, 0.22 and 0.15 mm ID are 2.06, 3.67, 3.82 and 3.47%, respectively.

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Section: Generalmentioning

confidence: 99%

Section: Prediction Of Peak Widths Of N-alkanes Eluted From Capillarymentioning

confidence: 99%

Prediction of gas chromatographic peak width in capillary columns at different temperatures, carrier gas flows, column lengths, inside diameters and carbon numbers

Krisnangkura

Pongtonkulpanich

2006

J of Separation Science

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“…Partindo da equação [7], Sie e Rijnders 11 , através de aproximações e rearranjos, chegaram na expressão ( )…”

Section: Efeito Da Pressão Sobre O Coeficiente De Partição (K)unclassified

Fluidos supercríticos em química analítica. I. Cromatografia com fluido supercrítico: conceitos termodinâmicos

Carrilho¹,

Tavares²,

Lanças³

2001

Quím. Nova

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Recebido em 15/6/00; aceito em 22/11/00 SUPERCRITICAL FLUID IN ANALYTICAL CHEMISTRY. I. SUPERCRITICAL FLUID CHROMATOGRAPHY: THERMODYNAMIC DEFINITIONS. Under the chromatographic point of view, the physico-chemical properties of a supercritical fluid are intermediate to those of the gases and liquids. Many times they approach the best features of each one, as for example, the solubilization power of liquids and low viscosity of gases. The thermodynamic definitions and main physico-chemical features of a supercritical fluid will be presented in this article. The use of supercritical fluids in analytical chemistry has been extremely modest in Brazil, even considering the enormous potential of their applications, and their use in several techniques, such as chromatography (SFC) and supercritical fluid extration (SFE). This article series is intended to discuss the historical evolution, instrumentation features and potential and limitations of the supercritical fluid use in analytical chemistry. A special focus will be centered on chromatography and extration techniques using supercritical fluids.Keywords: supercritical fluid; supercritical fluid chromatography; thermodynamic definitions. Quim. Nova, Vol. 24, No. 4, 509-515, 2001. Revisão INTRODUÇÃOApesar da descoberta do grande poder de solubilização dos fluidos supercríticos ter ocorrido no final do século XIX 1 , seu uso em química, e particularmente em química analítica, somente se verificou quase um século depois, no final do século XX 2 . Ainda assim, o uso de fluidos supercríticos em química analítica tem sido extremamente modesto no Brasil, fato não justificado considerando-se o enorme potencial de aplicação dos mesmos em várias técnicas, destacando-se a cromatografia com fluido supercrítico (SFC, do inglês supercritical fluid chromatography) e a extração com fluido supercrítico (SFE, do inglês supercritical fluid extraction). Nesta série de artigos pretende-se discutir a evolução histórica, principais caracterís-ticas, instrumentação, potencial e limitações do uso de fluidos supercríticos em química analítica, principalmente as técnicas de cromatografia e extração com fluido supercrítico.Quando um composto é confinado em um espaço determinado, gás e líquido estão em equilíbrio entre si. Aquecendo-se o sistema, as propriedades intrínsecas de ambos convergem para um mesmo ponto até serem idênticas (por exemplo, densidade, viscosidade, índice de refração, condutividade térmica, etc.). Este ponto é denominado ponto crítico 3 , e nele acaba-se a interface gás/líquido, pois a partir deste ponto encontra-se uma única fase supercrítica. Fluido supercrítico é portanto toda substância que se encontrar em condições de pressão e temperatura superiores aos seus parâmetros críticos. Essa região é melhor visualizada no diagrama de fases da Figura 1.Hannay e Hogarth 1 foram os primeiros a descobrir o grande poder de solvatação dos fluidos supercríticos quando estudaram a solubilidade de cloretos metálicos em etanol supercrítico. Apenas 10 anos após o advento da cromatografia...

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“…In the middle of the last century, Martin and Synge [1] had developed a technique for separating small molecules, such as amino acids, by column liquid chromatography. Their work evoked strong attention and resulted in a Nobel Prize in chemistry in 1952.…”

mentioning

confidence: 99%