Using strong injection solvents with 100% aqueous mobile phase in RP-LC

• Published in: Journal of separation science Vol. 29; no. 18; pp. 2847 - 2852
• Main Authors: Loeser, Eric, Drumm, Patrick
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.12.2006; WILEY‐VCH Verlag; Wiley
• Subjects: Analytical chemistry; Band broadening; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography, High Pressure Liquid - methods; Diluent; Exact sciences and technology; Injection effects; Other chromatographic methods; Peak shape abnormalities; Solvent strength; Solvents - chemistry; Spectrophotometry, Ultraviolet; Diluent; Water; Solvent effect; Peak resolution; Line shape; HPLC chromatography; uent / Injection effects / Peak shape abnormalities / Solvent strength; Injection; Mobile phase; Reversed phase chromatography; Line broadening; Ultraviolet detector; Carboxylic acid; Band broadening
• ISSN: 1615-9306; 1615-9314
• DOI: 10.1002/jssc.200600299

When samples are dissolved for HPLC analysis, organic solvents are often used to enhance the solubility of the sample components. However, when the diluent becomes significantly stronger than the mobile phase, peak shape distortions may develop during injection. This is a serious problem for weakly retained analytes under 100% aqueous mobile phase conditions. Under these extreme conditions, even small amounts of solvent in the diluent can cause serious broadening or distortion effects. However, if the organic solvent used in the diluent elutes significantly after the analyte, the peak shape of the analyte will be relatively unaffected, even when a relatively strong solvent such as THF is used. This phenomenon is counterintuitive considering the usual practice of keeping the sample diluent as weak as possible. This report describes the potential analytical utility and limitations of this approach for the analysis of weakly retained analytes.