Simultaneous Detection Of Anions Research Articles

Simultaneous Detection of Anions and Carbohydrates in Cyanobacteria by Two-Dimensional Ion Chromatography

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 analyzed separately making analysis long and tedious. A method combining two-dimensional ion chromatography (2D-IC) and valve switching was developed for the simultaneous determination of anions (F-, Cl-, NO2-, SO42-, NO3-, and PO43-) and carbohydrates (glycerin, glucosyl glycerol, trehalose, mannose, glucose, galactose, fructose, ribose, and sucrose) in cyanobacteria. Interfering color compounds were removed by first passing the sample through graphitized carbon 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. The following parameters were established: LOD, 0.001-0.030 (mg/L); LOQ, 0.001-0.010 (mg/L); linearity (R2), 0.9940; repeatability, 0.39-3.02%; and spiked recovery, 90.1-107%. The proposed method is adequately linear, accurate, and repeatable. The 2D-IC method provides fast, high-resolution, and completely automated procedure for the simultaneous determination of anions and carbohydrates without co-elution compared to the 1D ion chromatography method. This study provides application perspectives for use in biotechnology and other research fields. An accurate and effective 2D-IC method was developed for determining anions and carbohydrates in cyanobacteria. The method includes pre-treating samples with graphitized carbon SPE cartridges.

Simultaneous detection of anions and cations in mineral water by two dimensional ion chromatography

A two dimensional ion chromatography (2D-IC) method was improved for the simultaneous determination of six cations and seven anions using one-valve switching after injection and conductivity detector. The trap conditions and valve-switch timing were optimized. The method has good accuracy and sensitivity for the simultaneous separation of inorganic anions and cations with a mean correlation coefficient of >0.99, repeatability of 0.60%–3.0% for eight replicates, reproducibility of 0.78%–3.1%, and spiked recovery rate of 88.7%–110%. The method was successfully applied to the analysis of inorganic anions and cations in four kinds of mineral water and can completely satisfy the demand of water quality monitoring.

Simultaneous Analysis of Monovalent Anions and Cations with a Sub-Microliter Dead-Volume Flow-Through Potentiometric Detector for Ion Chromatography.

A microliter dead-volume flow-through cell as a potentiometric detector is described in this article for sensitive, selective and simultaneous detection of common monovalent anions and cations in single column ion chromatography for the first time. The detection cell consisted of less selective anion- and cation-selective composite membrane electrodes together with a solid-state composite matrix reference electrode. The simultaneous separation and sensitive detection of sodium (Na(+)), potassium (K(+)), ammonium (NH4 (+)), chloride (Cl(-)) and nitrate (NO3 (-)) in a single run was achieved by using 98% 1.5 mM MgSO4 and 2% acetonitrile eluent with a mixed-bed ion-exchange separation column without suppressor column system. The separation and simultaneous detection of the anions and cations were completed in 6 min at the eluent flow-rate of 0.8 mL/min. Detection limits, at S/N = 3, were ranged from 0.2 to 1.0 µM for the anions and 0.3 to 3.0 µM for the cations, respectively. The developed method was successfully applied to the simultaneous determination of monovalent anions and cations in several environmental and biological samples.

A novel method for analysis of explosives residue by simultaneous detection of anions and cations via capillary zone electrophoresis

A novel electrolyte has been developed for the simultaneous separation of cations and anions in low explosive residue by capillary electrophoresis. This electrolyte contains 15 mM α-hydroxyisobutyric acid (HIBA) as the buffer, 6 mM imidazole as the cation chromophore, 3 mM 1,3,6-naphthalenetrisulfonic acid (NTS) as the anion chromophore, 4 mM 18-crown-6 ether as a cation selectivity modifier, and 5% (v/v) acetonitrile as an organic modifier. The pH was adjusted to 6.5 using tetramethylammonium hydroxide (TMAOH), an electroosmotic flow modifier. The method was optimized by varying the concentrations of α-HIBA, imidazole, and 1,3,6-NTS at three different pH values. The results provided a simultaneous indirect photometric analysis of both anions and cations with detection limits ranging from 0.5 to 5 ppm for anions and from 10 to 15 ppm for cations with a total run time of under 7 min. The method was then applied to the analysis of Pyrodex ® RS and black powder, as well as several smokeless powders. The results obtained were consistent with previously reported results for separate anion and cation analysis and provide a faster, more complete analysis of each sample in a single chromatographic run.