Determination of Saccharides in Cottonseed Processing Waste Liquid and By-Products by High Performance Liquid Chromatography with Evaporative Light Scattering Detection (HPLC-ELSD)

A method utilizing high-performance liquid chromatography with evaporative light scattering detection (HPLC-ELSD) has been developed and validated for the simultaneous determination of raffinose, glucose, sucrose, and stachyose in waste liquid from cottonseed processing and in byproducts including cottonseed meal. The separation was performed using a carbohydrate ES column (250 × 4.6 mm, 5 μm) and isocratic elution with acetonitrile and water (70:30, v/v). The temperature of the column oven was maintained at 35 °C. The drift tube temperature for evaporative light scattering detection (ELSD) was operated 40 °C, while the nitrogen flow was set to 1.5 L·min−1. The saccharides were separated by HPLC-ELSD within 20 min. The coefficients of determination (R2 = 0.9986–0.9999) indicate that there was a linear relationship between saccharides and the response. The limits of detection were 0.004–0.023 mg·mL−1 and the quantification range was from 0.013 to 0.080 mg·mL−1. The intraday and interday precision were from 0.05 to 0.55% and 0.20 to 0.58%, respectively. The recovery was from 102.75 ± 2.03% to 106.76 ± 2.09% and the relative standard deviations were 1.87 to 1.98%. The method exhibited good stability in determining four saccharides in cottonseed processing waste liquid and the resultant byproduct cottonseed meal. This method exhibits high separation efficiency and sensitivity, excellent precision, and simplicity, which allows determination of the high value-added product, raffinose, in cottonseed processing waste liquid and meal.