title: A chromatographic objective function to characterise chromatograms with unknown compounds or without standards available.
abstract: Getting useful chemical information from samples containing many compounds is still a challenge to analysts in liquid chromatography. The highest complexity corresponds to samples for which there is no prior knowledge about their chemical composition. Computer-based methodologies are currently considered as the most efficient tools to optimise the chromatographic resolution, and further finding the optimal separation conditions. However, most chromatographic objective functions (COFs) described in the literature to measure the resolution are based on mathematical models fitted with the information obtained from standards, and cannot be applied to samples with unknown compounds. In this work, a new COF based on the automatic measurement of the protruding part of the chromatographic peaks (or peak prominences) that indicates the number of perceptible peaks and global resolution, without the need of standards, is developed. The proposed COF was found satisfactory with regard to the peak purity criterion when applied to artificial peaks and simulated chromatograms of mixtures built using the information of standards. The approach was applied to mixtures of drugs containing unknown impurities and degradation products and to extracts of medicinal herbs, eluted with acetonitrile-water mixtures using isocratic and gradient elution.
authors.affiliation: Departament de Química Analítica, Universitat de València, c/ Dr. Moliner 50, 46100 Burjassot, Valencia, Spain.
authors.forename: T
authors.initials: T
authors.lastname: Alvarez-Segura
authors.affiliation: Departament de Química Analítica, Universitat de València, c/ Dr. Moliner 50, 46100 Burjassot, Valencia, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Gómez-Díaz
authors.affiliation: Departament de Química Analítica, Universitat de València, c/ Dr. Moliner 50, 46100 Burjassot, Valencia, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Ortiz-Bolsico
authors.affiliation: Departament de Química Analítica, Universitat de València, c/ Dr. Moliner 50, 46100 Burjassot, Valencia, Spain. Electronic address: jrtorres@uv.es.
authors.forename: J R
authors.initials: JR
authors.lastname: Torres-Lapasió
authors.affiliation: Departament de Química Analítica, Universitat de València, c/ Dr. Moliner 50, 46100 Burjassot, Valencia, Spain.
authors.forename: M C
authors.initials: MC
authors.lastname: García-Alvarez-Coque
mesh_terms: D000097:Acetonitriles; D002853:Chromatography, Liquid / Q000379:methods*; D004340:Drug Contamination; D004364:Pharmaceutical Preparations / Q000032:analysis; D010936:Plant Extracts / Q000032:analysis; D012997:Solvents; D014867:Water
chemical_list: D000097:Acetonitriles; D004364:Pharmaceutical Preparations; D010936:Plant Extracts; D012997:Solvents; D014867:Water; C032159:acetonitrile
keywords: Chromatographic objective function; Complex samples; Liquid chromatography; Peak count; Resolution; Unknown compounds