Complete Temperature Profiles in Ultra-High-Pressure Liquid Chromatography Columns

• Published in: Analytical chemistry (Washington) Vol. 80; no. 13; pp. 5009 - 5020
• Main Authors: Gritti, Fabrice, Guiochon, Georges
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-07-2008
• Subjects: ACCURACY; ACETONITRILE; AIR; Analytical chemistry; BOUNDARY CONDITIONS; Chemistry; Chromatographic methods and physical methods associated with chromatography; CHROMATOGRAPHY; Chromatography, High Pressure Liquid - instrumentation; Chromatography, High Pressure Liquid - methods; COMPRESSIBILITY; CONVECTION; Exact sciences and technology; EXTRACTION COLUMNS; FLOW RATE; FORECASTING; MATERIALS SCIENCE; Models, Chemical; Other chromatographic methods; Pressure; PRESSURE DROP; Silicon Dioxide - chemistry; Siloxanes - chemistry; STAINLESS STEELS; Temperature; TEMPERATURE GRADIENTS; THERMAL EXPANSION; Thermodynamics; Liquid column; Liquid chromatography; Air; Boundary condition; Convection; Temperature gradient; High pressure; Pressure drop; Stainless steel; Acetonitrile; Column chromatography; Packed column; Room temperature
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac800280c

The temperature profiles were calculated along and across seven packed columns (lengths 30, 50, 100, and 150 mm, i.d., 1 and 2.1 mm, all packed with Acquity UPLC, BEH-C 18 particles, average d p ≈ 1.7 μm) and their stainless steel tubes (o.d. 4.53 and 6.35 mm). These columns were kept horizontal and sheltered from forced air convection (i.e., under still air conditions), at room temperature. They were all percolated with pure acetonitrile, either under the maximum pressure drop (1034 bar) or at the maximum flow rate (2 mL/min) permitted by the chromatograph. The heat balance equation of chromatographic columns was discretized and solved numerically with minimum approximation. Both the compressibility and the thermal expansion of the eluent were taken into account. The boundary conditions were determined from the experimental measurements of the column inlet pressure and of the temperature profile along the column wall, which were made with a precision better than ±0.1 K. These calculation results provide the 3-D temperature profiles along and across the columns. The axial and radial temperature gradients are discussed in relationship with the experimental conditions used. The temperature map obtained permits a prediction of the chromatographic data obtained under a very high pressure gradient.