Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 4C) pdf

... Applications in the Pharmaceutical Industry. Since a great major- ity of drugs include basic functional groups, HPLC behavior of basic com- pounds has attracted significant interest [183]. Therefore, reversed-phase HPLC ... might be obtained for the basic analyte in its neutral form.The advan- tages of employing chaotropic mobile-phase additives at a pH where the basic analyte is in it...

Ngày tải lên: 24/12/2013, 18:15

... by the pressure limitation of the HPLC equipment. For more information on gradient separation and developing fast HPLC methods, see Chapter 17 and Practical HPLC Method Development from Synder ... chromatographic selectivity for a set of compounds, bonded phase stability, and lot-to-lot reproducibility). The criteria for selec- tion may include that the column is stable for a ce...

Ngày tải lên: 15/12/2013, 12:15

... The experiments for w w pH 2–4 were performed on day 1, and those for w w pH 5–7 were performed on day 2 (≈36 hr after initial prepa- ration).A further investigation was performed by preparing ... down the right path for initial mobile- phase pH selection. In the following case study for this pharmaceutical compound M, the method development scenario and rationale for each itera...

Ngày tải lên: 15/12/2013, 12:15

... down the right path for initial mobile- phase pH selection. In the following case study for this pharmaceutical compound M, the method development scenario and rationale for each iteration in ... Figure 8-40A for the sample stored in the acidic diluent for 4 days at room temperature shows some degradation compared to Figure 8-40B for the sample stored in the acidic diluent for...

Ngày tải lên: 15/12/2013, 12:15

... pK a for the target analyte and related impurities is particu- larly useful for commencement of method development of HPLC methods for key raw materials, reaction monitoring, and active pharmaceutical ... same critical distance (D) needed for ion-pair formation, a solvent with a high dielectric constant such as water (∼80) will be less favorable for ion-pair formation compared t...

Ngày tải lên: 24/12/2013, 18:15

... decreases, retention in normal-phase chromatography 241 HPLC for Pharmaceutical Scientists, Edited by Yuri Kazakevich and Rosario LoBrutto Copyright © 2007 by John Wiley & Sons, Inc. Carbohydrates ... REFERENCES 259 5 NORMAL-PHASE HPLC Yong Liu and Anant Vailaya 5.1 INTRODUCTION High-performance liquid chromatography (HPLC) is a separation tool par excellence for the analysi...

Ngày tải lên: 24/12/2013, 18:15

... (i.e., spanning target identification → chemical 535 HPLC for Pharmaceutical Scientists, Edited by Yuri Kazakevich and Rosario LoBrutto Copyright © 2007 by John Wiley & Sons, Inc. registration ... chro- matographic peaks for a given sample will be hard to predict, and therefore the footprint for fraction collection will be difficult to predict. Experience has shown that it is n...

Ngày tải lên: 22/01/2014, 00:20

... eluent for reversed- phase high performance liquid chromatography, Anal. Commun. 33 (1996), 327–329. 57. R. M. Smith and R. J. Burgess, Superheated water as an eluent for reversed-phase high performance ... in pharmaceutical analysis. The precise and accurate control of temperature can improve repro- ducibility and method transferability (Section 18.2). In recent years, the use of 811...

Ngày tải lên: 22/01/2014, 00:20

... oxidized forms of hyperforin by HPLC- NMR and HPLC- MS n , Phytochem. Anal. 14 (2003), 290–297. 94. J. K. Roberts and R. J. Smith, Use of liquid chromatography–Nuclear magnetic resonance spectroscopy for ... Reversed-phase HPLC of the samples was carried out on a Varian modular HPLC system (a 9012 pump and a 9065 photodiode array UV detector).The Varian HPLC software was also equipp...

Ngày tải lên: 26/01/2014, 19:20

... ions on the basis of mass-to-charge ratios, 281 HPLC for Pharmaceutical Scientists, Edited by Yuri Kazakevich and Rosario LoBrutto Copyright © 2007 by John Wiley & Sons, Inc. 150°C, depending ... flow to about 400°C for over 50 µL/min of solvent flow. For LC/APCI-MS, the APCI probe temperature is normally set at 400°C, which can be higher for involatile samples or lower for...

Ngày tải lên: 15/12/2013, 12:15