Ion chromatography
IndustriesFood & Agriculture
ManufacturerThermo Fisher Scientific
Significance of the Topic
Sucralose is a widely used nonnutritive sweetener in foods and beverages. Its lack of a UV chromophore and coelution with chromophoric ingredients make detection by conventional UV or refractive index challenging. High-performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAE-PAD) provides the specificity and sensitivity needed for trace analysis of sucralose in complex matrices.
Objectives and Study Overview
This work aimed to develop and validate isocratic and gradient HPAE-PAD methods using a CarboPac PA20 column to quantify sucralose in model samples: Red Raspberry Diet Rite and Splenda sugar substitute. Performance metrics included linearity, limits of detection and quantification, precision, recovery, and applicability to real samples.
Methodology and Instrumentation
- System: Dionex BioLC with GP50 microbore pump, AS50 autosampler in thermal compartment and ED50 electrochemical detector.
- Column: CarboPac PA20 analytical column with guard.
- Detection: Pulsed amperometric detection using disposable gold working electrodes; carbohydrate waveform (alternative AAA-Direct waveform for enhanced sensitivity).
- Eluents: Water (A), 40–250 mM NaOH (B), 75–800 mM sodium acetate (C). Both isocratic (40 mM NaOH + 75 mM acetate) and gradient methods were optimized.
- Sample prep: 10 mg/mL sucralose stock in water; Diet Rite diluted 50-fold; Splenda dissolved to 100 mg/mL, diluted to 100 µg/mL.
Main Results and Discussion
- Linearity: Peak area response linear from 1.24 to 250 pmol (r² ≥ 0.9958), extending to 1000 pmol within 20% variance.
- Sensitivity: LOD of 0.28 pmol (0.01 µM) and LOQ of 0.93 pmol (0.04 µM) for a 25 µL injection.
- Precision: Retention time RSD 0.7–1.2% and peak area RSD 2.4–3.0% over seven days (836 injections) with periodic column washes.
- Recovery: Spike recoveries of 92–96% for sucralose in diluted Diet Rite across multiple dilution levels.
- Sample quantification: Sucralose at 155 µg/mL (390 µM) in Diet Rite; in Splenda, sucralose was 1.4% w/w and dextrose 85% w/w.
- Gradient method enabled simultaneous dextrose and sucralose separation, with system peaks identified and excluded from quantification.
Benefits and Practical Applications
- High specificity for oxidizable sweeteners in complex matrices.
- Broad dynamic range covering trace to high concentrations.
- Minimal interference from non-oxidizable components.
- Robustness and reproducibility suitable for routine quality control in food and beverage analysis.
Future Trends and Applications
- Coupling HPAE-PAD with mass spectrometry for confirmatory analyses.
- Development of miniaturized, high-throughput platforms for regulatory screening.
- Advances in electrode materials and pulsed waveforms to enhance sensitivity and electrode lifespan.
- Extension to emerging sweetener analogues and diverse food matrices such as dairy and pharmaceuticals.
Conclusion
The optimized HPAE-PAD protocols using a CarboPac PA20 column deliver sensitive, precise, and robust determination of sucralose in food and beverage products. Both isocratic and gradient approaches effectively separate sucralose from matrix interferences, enabling accurate quantification for routine QA/QC applications.
References
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- Quinlan M.E., Jenner M.R. Analysis and Stability of the Sweetener Sucralose in Beverages. J Food Sci. 1990;55:244–246.
- Dionex Corporation. The Determination of Carbohydrates, Alcohols, and Glycols in Fermentation Broths; Application Note 122; Sunnyvale, CA.
- Dionex Corporation. Determination of Amino Acids in Cell Cultures and Fermentation Broths; Application Note 150; Sunnyvale, CA.
- Kobayashi C., Nakazato M., Yamajima Y., Ohno I., Kawano M., Yasuda K. Determination of Sucralose in Foods by HPLC. Shokuhin Eiseigaku Zasshi. 2001;42:139–143.
- Kishi H., Kawana K. Determination of Sucralose in Foods by Anion-Exchange Chromatography and Reverse-Phase Chromatography. Shokuhin Eiseigaku Zasshi. 2001;42:133–138.
- Dionex Corporation. Optimal Settings for Pulsed Amperometric Detection of Carbohydrates Using the Dionex ED40 Electrochemical Detector; Technical Note 21; Sunnyvale, CA.
- Dionex Corporation. AAA-Direct Amino Acid Analysis System; Product Manual 031481; Sunnyvale, CA.
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