Study of ion distribution in microcrystalline cellulose and its correlation with conductivity using ion chromatography

LIU Jing-lan; WANG Jue; CHEN Hui-lin; ZHENG Shu-feng; YANG Rui; ZHAO Xia

doi:10.20251/j.cnki.1003-3734.2025.03.014

Abstract：Objective:To develop ion chromatography methods for the determination of five anions(CH3COO-,HCOO-,Cl-,N03-,SO42-)and five cations(Na+,NH4+,K+,Mg2+,Ca2+)in microcrystalline cellulose,to investigate the relationship between changes in conductivity and ion concentrations,and to provide suggestions for its quality control measures.Methods:The determination of anions was performed using a Dionex IonPac AS19 column(250 mm ×4.0 mm,5 μm)equipped with an ASRS 300 suppressor(4 mm)and utilizing 15 mmol·L-1 potassium hydroxide as the eluent.For cation ayalysis,a Dionex IonPac CS19 column(250 mm × 4.0 mm,5 μm)was used with a CSRS 300 suppressor(4 mm)and 15 mmol·L-1 methane sulfonic acid serving as the eluent.The flow rate was maintained at 1.0 mL·min-1,the suppression conductivity detection(current of suppressor was 44 mA)was used,the conductivity cell temperature was 35 ℃,the column temperature was kept at 30 ℃,the injection volume was 25 μL,and the quantitative concentrations of 10 ions were determined using standard curve methodology.Based on the conductivity values at different time points in the stability test of microcrystalline cellulose,grey correlation analysis between conductivity and ion concentration was performed using a grey correlation model.Results:The mass concentration of 10 ions showed a good linear relationship with their respective peak areas,with all correlation coefficients above 0.999.The limits of quantitation ranged 0.02～2.81 ng,while the limits of detection ranged 0.01～0.89 ng,and the average recoveries were 92.8％～101.3％(n=6).The changes in conductivity of microcrystalline cellulose has a significant correlation coefficient with both Na+and Cl-.Conclusion:This method is simple,rapid,specific and universally applicable,making it suitable for the determination of multiple anions and cations in microcrystalline cellulose,while grey correlation analysis between conductivity and ion distribution provides data reference for its quality control.