P. Härmälä

Optimization of the high-performance liquid chromatography of coumarins in Angelica archangelica with reference to molecular structure

Abstract Molecular connectivity indices were calculated and compared with measured isocratic and gradient (binary gradient and isoselective multi-solvent gradient) reversed-phase high-performance liquid chromatographic retention data of ten coumarins in Angelica archangelica. Retention measurements were performed, using organic solvent—water eluents, containing methanol, ethanol, 1-propanol, tetrahydrofuran, dioxane, acetonitrile and their mixtures, according to the “PRISMA” model in the optimization process. The solvent strength values were obtained experimentally. A baseline separation of the ten coumarins was achieved. The elution order of the coumarins varied according to the solvent. Decreasing the volume fraction in many instances increased the separation factor. The compounds were divided into two groups. The path type of the fourth-order and path/cluster type of the fourth-order valence level indices best described the retention. High correlations were observed between the calculated and measured retentions. The retention could be well predicted for different selectivity points in the “PRISMA” using the molecular connectivity indices.

Methods for detection of irradiation of spices

ZusammenfassungEs wurden drei Methoden als eventuelle Kontrollverfahren zum Nachweis einer Gewürzbestrahlung getestet: Mikrobiologische Verfahren, die sich aus unmittelbar auf Epifluorescenzmikroskopie (DEFT) und Kolonieauszählung (APC) basierenden Verfahren zusammensetzen, ein Chemiluminescenzverfahren sowie chemische gaschromatographische (GC) und GC-massenspektrometrische (MS) Verfahren zum Analysieren der von den Gewürzen durch Wasserdampfdestillation abgetrennten flüchtigen Öle. Zwölf Gewürzproben, hauptsächlich Pfeffer, wurden vor und nach der Gammabestrahlung analysiert; die Strahlendosen betrugen 10 und 50 kGy. Die Chemiluminescenzmessungen erfolgten vor und 10 sowie 100 Tage nach der Bestrahlung. Am besten geeignet für die Kontrollzwecke erwiesen sich die mikrobiologischen Verfahren (DEFT+APC), ergänzt durch Chemiluminescenzmessungen. Mit den chemischen Verfahren wurden keine Unterschiede zwischen bestrahlten und unbestrahlten Proben festgestellt.AbstractThree types of methods for the identification of irradiation of spices were tested as potential control methods. The methods were microbiological, combining a direct epifluorescent filter technique (DEFT) with a total aerobic plate count (APC), a chemiluminescence method and chemical gas-chromatographic (GC) and GC mass-spectrometric (MS) methods for analysis of volatile oils of spices isolated by steam distillation. Twelve samples of spices, mainly peppers, were analysed before and after gamma-irradiation with doses of 10 and 50 kGy. The chemiluminescence measurements were performed before the irradiation and 10 and 100 days after the irradiation. The best methods for control purposes were the microbiological (DEFT+APC) methods combined with chemiluminescence measurements. No differences were detected between the irradiated and non-irradiated samples with the chemical methods.

Retention behaviour of closely related coumarins in thin-layer chromatographic preassays for high-performance liquid chromatography according to the “PRISMA” model

Abstract The retention behaviour of fourteen closely related coumarins in normal-phase thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) was studied with the aim of testing the suitability of TLC as a preassay for HPLC when the optimization of the mobile phase has been carried out according to the “PRISMA” system. The retention (retardation) in TLC and HPLC was measured at 37 and 13 selective points, respectively. The retention behaviour at different solvent strengths was also examined. Capacity factors ( k ′) and separation factors (α) were calculated to study the retention behaviour in the two systems. Two- and three-dimensional evaluations of k ′ against selectivity points showed similar retention behaviour for the coumarins in TLC and HPLC. According to quadratic regression, k ′ showed a dependency on the change in solvent strength. Similar behaviour of α values for TLC and for HPLC was demonstrated in three-dimensional evaluations.