Simultaneous detection of anions and carbohydrates in cyanobacteria by two-dimensional ion chromatography

Background The simultaneous analysis of several anions and carbohydrates by one-dimensional chromatography with a single detector is often complicated by the presence of overlapping peaks. To overcome this problem, analytes are usually analysed separately making analysis long and tedious. Objective A method combining two-dimensional ion chromatography (2 D-IC) and valve switching was developed for the simultaneous determination of anions (F−, Cl−, NO2−, SO42−, NO3−, and PO43−) and carbohydrates (glycerinum, glucosyl glycerol, trehalose, mannose, glucose, galactose, fructose, ribose, and sucrose) in cyanobacteria. Methods Interfering color compounds were removed by first passing the sample through graphitized carbom solid phase extraction (SPE) cartridges. Samples were applied to an AS11-HC column, which was used to separate the anions followed by quantification using a conductance detector. Carbohydrates eluted from the AS11-HC column were trapped and separated on a MA1 column and simultaneously quantified using electrochemical detection in the second dimension with valve switching. Results The following parameters were established: LOD, 0.001–0.030 (mg/L); LOQ, 0.001–0.010 (mg/L); linearity (r), 0.9940; repeatability, 0.39%–3.02%; and spiked recovery, 90.1%–107%. Conclusion The proposed method is adequately linear, accurate, and repeatable. The 2 D-IC method provides fast, high resolution, and completely automated procedure for the simultaneous determination of anions and carbohydrates without co-elution compared to the one dimension ion chromatography method. This study provides application perspectives for use in biotechnology and other research fields. Highlights An accurate and effective 2 D-IC method was developed for determining anions and carbohydrates in cyanobacteria. The method includes pre-treating samples with graphitized carbon SPE cartridges.