Sensitive Analysis of Commonly Used Artificial and Natural Sweeteners Including Stevia and Their Impurities and Degradation Products

Abstract

Many recently commercialized sweeteners tend to have increased potency, reducing the amount of active ingredient added to beverages and other food products and often providing cost savings to the manufacturer. Using increased potency has also contributed to a need for sensitive analytical methods to quantify the active product and to detect low levels of breakdown products and impurities, which are required for quality and safety issues. Because compounds typically do not possess any chromophore, traditional HPLC-UV approaches are inappropriate. The work in this study describes several methods using HPLC with the Thermo Scientific Dionex CoronaTM Charged Aerosol Detector (CADTM) for the study of common natural sugars (fructose, glucose, turanose, saccharose, trehalose, maltose, melezitose, and raffinose); artificial sweeteners (sucralose, aspartame, saccharin, and acesulfame K); and newly introduced products containing stevia extracts (rebaudioside A and stevioside). These HPLC-CAD methods provide sensitivity at low levels (ng) with good reproducibility and accuracy, and correlation to the component concentrations. Stevia products were analyzed by both charged aerosol detection and UV. Charged aerosol detection showed a greater than fivefold improvement in sensitivity over UV for all major components. Finally, the UHPLC methods developed showed a decreased run time and an increased sensitivity for glucose, lactose, and sucrose. Typical limits of detection (LOD) were found to be <500 pg (on column) for glucose and other monoand disaccharides. HPLC-CAD is a very flexible approach to measuring sweeteners and overcomes many of the limitations of UV, refractive index (RI), LCMS, evaporative light scattering detection (ELSD), and HPLC-pulsed amperometric approaches. The HPLC-CAD platform can be used throughout the manufacturing process to ensure finished quality and batch-to-batch uniformity. Introduction The Dionex Corona CAD is a mass-sensitive universal detector for nonvolatile and some semivolatile analytes. Unlike absorbance, fluorescence, RI, or electrochemical detection, analyte response is independent of chemical Sensitive Analysis of Commonly Used Artificial and Natural Sweeteners Including Stevia and Their Impurities and Degradation Products Ian Acworth, Chris Crafts, and Bruce Bailey, Thermo Fisher Scientific, Chelmsford, MA, USA structure. Carbohydrates lack chromophores and the typical approaches used for their analysis may lack sensitivity, require derivatization, or cannot be used with gradient. The work in this study examines different HPLC-CAD methods for the analysis of honey sugars, artificial sweeteners, and other natural products including stevia extracts. Finally, a new UHPLC method for fast analysis of simple carbohydrates is presented. The Corona CAD system is easy to use and offers a simple, sensitive, reproducible, and direct approach for the routine analysis of natural and artificial sweeteners. Artificial Sweeteners Global Method HPLC Parameters Column: ACE®, C18 4.6 × 250 mm, 5 μm Mobile Phase: A) Deionized water B) Acetonitrile + 0.1% trifluoroacetic acid Gradient: 2 to 40% B over 25 min, 40 to 60% 25–30 min Flow Rate: 1.0 mL/min Inj. Volume: 50 μL Column Temp.: 30 °C Samples: 1.2 to 20 μg on column FIGURE 1. Chromatogram of artificial sweeteners. 26831 5 10 15 20 25 30 35 400 A ce su lfa m e K C yc la m at e S ac ch ar in S uc ra lo se A sp ar ta m e