Fast gradient separation by very high pressure liquid chromatography: Reproducibility of analytical data and influence of delay between successive runs

2013 ◽  
Vol 1318 ◽  
pp. 122-133 ◽  
Author(s):  
Joseph J. Stankovich ◽  
Fabrice Gritti ◽  
Lois Ann Beaver ◽  
Paul G. Stevenson ◽  
Georges Guiochon
2011 ◽  
Vol 94 (1) ◽  
pp. 51-70 ◽  
Author(s):  
Philippe J Eugster ◽  
Davy Guillarme ◽  
Serge Rudaz ◽  
Jean-Luc Veuthey ◽  
Pierre-Alain Carrupt ◽  
...  

Abstract Ultra high pressure liquid chromatography (UHPLC) systems operating at very high pressures and using sub-2 μm packing columns have allowed a remarkable decrease in analysis time and increase in peak capacity, sensitivity, and reproducibility compared to conventional HPLC. This technology has rapidly been widely accepted by the analytical community and is being gradually applied to various fields of plant analysis such as QC, profiling and fingerprinting, dereplication, and metabolomics. For many applications, an important improvement of the overall performances has been reported. In this review, the basic principles of UHPLC are summarized, and practical information on the type of columns used and phase chemistry available is provided. An overview of the latest applications to natural product analysis in complex mixtures is given, and the potential and limitations as well as some new trends in the development of UHPLC are discussed.


1988 ◽  
Vol 117 (1) ◽  
pp. 27-34 ◽  
Author(s):  
D. J. A. Eckland ◽  
K. Todd ◽  
S. L. Lightman

ABSTRACT Immunoreactive vasopressin and oxytocin were measured in the hypothalamo-hypophysial portal blood of both Long–Evans and homozygous Brattleboro rats. Adrenalectomy caused an increase in vasopressin immunoreactivity in portal blood in the Long–Evans strain, whilst administration of dexamethasone to these adrenalectomized animals resulted in a reduction in portal vasopressin immunoreactivity to levels below those seen in sham-operated animals. This vasopressin immunoreactivity co-eluted with synthetic vasopressin on high-pressure liquid chromatography (HPLC), and diluted in parallel in radioimmunoassay. In Brattleboro rats, however, although vasopressin-like immunoreactivity was detected, the portal concentration did not vary with the adrenal status of the animal, nor did it show the characteristics of standard vasopressin on HPLC or in immunoassay. Oxytocin was present in the portal blood of both Long–Evans and Brattleboro rats at similar very high concentrations, but did not vary in response to adrenalectomy. These results are consistent with a role for vasopressin, but not oxytocin, in the hypothalamic response to adrenalectomy and glucocorticoid feedback. Neither vasopressin immunoreactivity nor oxytocin appear to subserve this role in the homozygous Brattleboro rat. J. Endocr. (1988) 117, 27–34


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