UPLC, comparison with HPLC

FIGURE 7.10 Sensitivity comparison of HPLC and UPLC. The same sample was injected twice once using HPLC/MS/MS and again on a UPLC/MS/MS system (A) response for diphenhydramine on each system (B) response of ibuprofen. (Source Adapted from Yu, K. et al., Rapid Commun. Mass Spectrom., 2006, 20, 544. With permission of John Wiley Sons.)... 

FIGURE 10.2 Comparison of HPLC and UPLC for the separation of a ginger root extract. (Adapted from Swartz, E. 2005. J. Liq. Chromatogr. Related Technol. 28 1253-1263. With permission.)... 

The utility of UPLC has been demonstrated for both qualitative and quantitative analyses. In 2005, Castro-Perez et al. (2005) compared the performance of a HPLC with that of a UPLC and showed that improved chromatographic resolution and peak capacity attained with UPLC lead to reduction in ion suppression and increased MS sensitivity. Comparison of the mass spectrum obtained using HPLC with that from UPLC (Fig. 1.15) revealed that the higher resolving power of the UPLC-MS system resulted in a much cleaner mass spectrum than that obtained using the HPLC-MS system. The sensitivity improvement directly resulted in a higher ion count in the UPLC mass spectrum (855 vs. 176). 

Figure 1.16. Comparison of peak-to-peak (PtP) S/N ratio for the desmethyl-dextromethorphan-glucuronide (m/z 434.222) obtained using HPLC-MS (top trace) and UPLC-MS (bottom trace). (Reprinted with permission from Castro-Perez et al., 2005.)...

Figure 1.18. Comparison of MRM chromatograms following HPLC-MS/MS and UPLC-MS/ MS analysis of a mixture containing alprazolam, ibuprofen, d5-alprazolam, diphenhydramine, naproxen, and prednisolone. Each set of chromatograms was obtained from a single 100-ng/ mL injection of rat plasma. d5-Alprazolam was used as the internal standard for quantification of alprazolam. (Reprinted with pemnission from Yu et al., 2006.)...

FIGURE 11.1 Comparison of the extracted ion chromatograms for doubly hydro-xylated metabolites (m/z 406) of prochlorperazine from incubations with rat liver microsomes obtained from HPLC/MS (a) and UPLC/MS (b). Reprinted from Castro-Perez et al. (2005a) with permission of John Wiley and Sons Limited. 

UPLC can be regarded as a new invention for liquid chromatography. Compared with conventional HPLC, UPLC can offer significant improvements in speed, sensitivity, and resolution, which also mean reduced solvent consumption and analysis cost. Figure 10.2 shows an HPLC versus UPLC separation comparison of a ginger root extract sample, where both speed and resolution are improved, and sensitivity is increased [57]. 

In conclusion, the arrival of the UPLC in laboratories has permitted the improvement of the quality and the productivity of analyses, with an increased sensitivity, a better selectivity, a high throughput, and simplification of sample preparation. To increase the productivity of mass spectrometers, UPLC can also be a solution, with a reduction of run time, a better resolution, and better sensitivity, in comparison to classical HPLC systems. 

FIGURE13.3 Comparison study on the determination of acrylamide by (a) UPLC-MS/MS and (b) HPLC-MS/MS. (Adapted from Zhang, Y. et al. 2007. J. Chromatogr. A 1142 194-198. With permission.)... 

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