Separation of highly charged (+5 to +10) amphipathic α-helical peptide standards by cation-exchange and reversed-phase high-performance liquid chromatography

2018 ◽  
Vol 1574 ◽  
pp. 60-70 ◽  
Author(s):  
Colin T. Mant ◽  
Andrew Byars ◽  
Sean Ankarlo ◽  
Ziqing Jiang ◽  
Robert S. Hodges
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Cation Exchange ◽  
High Performance ◽  
Reversed Phase ◽  
Helical Peptide

Catecholamine measurements by high-performance liquid chromatography

1984 ◽  
Vol 247 (1) ◽  
pp. E13-E20 ◽  
Author(s):  
P. Hjemdahl
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Cation Exchange ◽  
High Performance ◽  
Reversed Phase ◽  
Exchange Chromatography ◽  
Lower Sensitivity ◽  
Tissue Samples ◽  
Basal Plasma ◽  
Postcolumn Derivatization

The development of sensitive detectors has allowed the use of high-performance liquid chromatography (HPLC) for measurements of catecholamines in extracts of plasma, urine, and tissue samples. Separation of the catecholamines may be effected by reversed phase chromatography or cation-exchange chromatography and quantitation by electrochemical detection (EC) or by fluorometry coupled with postcolumn derivatization according to the trihydroxyindole (THI) method. EC has a somewhat lower sensitivity than the THI method for norepinephrine (NE) and epinephrine (E). The THI method is insensitive to dopamine (DA). Basal plasma E levels of 0.1 nM (20 pg/ml) or less may be measured in sample volumes of 1-2 ml with EC. Sensitivity and reproducibility of an assay is not necessarily a guarantee of accuracy. It is argued that new methods and modifications of old methods should be validated against accepted methodology. This is rarely the case. Cation exchange HPLC with EC has been adequately validated, but only one of the reversed phase methods has been compared with radioenzymatic methodology. HPLC has the advantages of economy, speed, and more stimulating laboratory work, as compared with radioenzymatic methodology.

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