title: High-performance thin-layer chromatography analysis of steviol glycosides in Stevia formulations and sugar-free food products, and benchmarking with (ultra) high-performance liquid chromatography.
abstract: A high-performance TLC (HPTLC) method was newly developed and validated for analysis of 7 steviol glycosides in 6 different types of food and Stevia formulations. After a minimized one-step sample preparation, 21 samples were developed in parallel, allowing an effective food screening. Depending on the sample application volume, the method was suited to analyze food sample concentrations in the mg/kg range. LOQs of stevioside in natural yoghurt matrix spiked at 0.02, 0.13 and 0.2% were determined by the calibration curve method to be 12ng/band (peak height). ANOVA was successfully passed to prove data homogeneity in the working range (30-600ng/band). The accuracy (recovery tolerance limit, 92-120%), repeatability (3.1-5.4%) and intermediate precision (4.0-8.4%) were determined for stevioside in milk-based matrix including sample preparation and recovery rates at 3 different concentration levels. For the first time, the recording of HPTLC-ESI-MS spectra via the TLC-MS Interface was demonstrated for rebaudioside A. HPTLC contents for rebaudioside A were compared with results of two (U)HPLC methods. The running costs and analysis time of the three different methods were discussed in detail with regard to screening of food products.
authors.affiliation: Institute of Nutritional Science, Chair of Food Science, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany. Electronic address: Gertrud.Morlock@ernaehrung.uni-giessen.de.
authors.forename: Gertrud E
authors.initials: GE
authors.lastname: Morlock
authors.affiliation: Institute of Nutritional Science, Chair of Food Science, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Meyer
authors.affiliation: Institute of Nutrition and Food Sciences, University of Bonn, Römerstr. 164, 53117 Bonn, Germany; Institut Prof. Dr. Georg Kurz GmbH, Eupener Str. 161, 50933 Köln, Germany.
authors.forename: Benno F
authors.initials: BF
authors.lastname: Zimmermann
authors.affiliation: Analytical Methods Development and Validation Consulting, Chemin Saint Jacques, 13100 Le Tholonet, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Roussel
mesh_terms: D019985:Benchmarking; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D045786:Diterpenes, Kaurane / Q000737:chemistry; D005504:Food Analysis / Q000379:methods*; D006027:Glycosides / Q000032:analysis* / Q000737:chemistry; D036625:Stevia / Q000737:chemistry*; D013549:Sweetening Agents / Q000737:chemistry*
chemical_list: D045786:Diterpenes, Kaurane; D006027:Glycosides; D013549:Sweetening Agents; C012042:steviol
keywords: Food additives; Food safety; HPTLC–MS; High-performance thin-layer chromatography; Stevia rebaudiana; Sweetener