Improved evaporative light scattering detection for carbohydrate analysis

• Optimization of ELS detection by RSM for the analysis of carbohydrates.
• ELSD–HPSEC analysis of a wide molecular range of carbohydrates.
• Log-regression curves for carbohydrate standards show a good correlation.
• Precision is lower than 1.8% relative standard deviation.
• Recovery values show the fairly good accuracy of the analysis.

Optimization and validation of evaporative light scattering detector (ELSD), aided by response surface methodology (RSM), has been developed for the liquid chromatography analysis of a wide molecular weight (MW) range of carbohydrates, including polysaccharides and oligosaccharides. Optimal experimental parameters for the ELSD detection were: 88.8 °C evaporator temperature, 77.9 °C nebulizer temperature and 1.1 standard litres per minute nitrogen flow rate. Optimal ELSD detection, used together with high performance size exclusion chromatography (HPSEC) of carbohydrates, gave a linear range from 250 to 1000 mg L−1 (R2 > 0.998), with limits of detection and quantitation of 4.83–11.67 and 16.11–38.91 mg L−1, respectively. Relative standard deviation was lower than 1.8% for intra-day and inter-day repeatability for apple pectin, inulin, verbascose, stachyose and raffinose. Recovery ranged from 103.7% to 118.3% for fructo-oligosaccharides, α-galacto-oligosaccharides and disaccharides. Optimized and validated ELSD detection is proposed for the analysis of high- to low-MW carbohydrates with high sensitivity, precision and accuracy.