UHPLC/UPLC columns

Figure 9.3 shows an impurity separation under conventional pressures with a 5 /mi particle, 2.1 x 150 mm column, and the same separation performed via UPLC using a 2.1 x 50 mm column with 1.7 /im particles. The run time was improved by a factor of six, with overall resolution comparable to that of the original separation on the 5 /an column. The application of UHPLC technology to impurity profile analysis can exert a significant impact on laboratory productivity by achieving a... 

Figure 23.5 Separation with UHPLC [after T. Moritz, Nestle Research Center, Lausanne, with permission see also S.J. Bruce et a .. Anal. Biochem., 372, 237 (2008)]. Conditions sample, extract from human plasma column, 10 cm 2.1mm i.d. stationary phase, C8 UPLC 1.7pm mobile phase, 0.5mlmin water-acetonitrile with 0.1% formic acid, linear gradient pressure, 600 bar detector, TOF-MS with positive ESI. The first peaks are amino acids and low-mass metabolites, the ones between 8 and 11 min are phospholipids (besides background peaks). 

VOO TAG profile, and checked the possibility of using this technique as a tool for VOO adulteration control. In this study, the sample preparation consisted, as was the case for the HPLC-MS methods previously described, of a simple dilution of the oils in 2-propanol. The separation was carried out by means of a UHPLC system with a packed column of the following characteristics 2.1 x 150 mm UPLC 1.7 pm BEH C18. 

Most conventional pumps operate at pressures up to 400 bar, while some ultra-high pressure systems may operate at as high as 1000-1200bar. Ultrahigh-pressure LC (UPLC or UHPLC) requires special made columns and connections for the high pressures. The high pressures are a result of columns packed with very small particles. 

Wang et al. (47) developed a rapid and sensitive method to determine lovastatin in human plasma with sinvastatin as an internal standard using UHPLC-MS/MS. The analysis was carried out on an ACQUITY UPLC BEH Cig column. The calibration curve of this method was found to be linear over the concentration range of 0.025 to 50 ng/mL. The lower limit of quantification for lovastatin was 0.025 ng/mL. The interday and intraday precision (relative standard deviation) were less than 11%, and the accuracy (relative error) was within 6.0%. The analysis time was shorter than 1.7 min per sample, which met a high-throughput determination of biological samples. 

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