Simultaneous Determination Of Inorganic Cations Research Articles

Dual-column Switching Ion Chromatography for the Simultaneous Determination of Inorganic Cations and Anions (particularly Thiocyanate) in Human Urine and Saliva Samples to Identify Smokers Types

An ion chromatography (IC) have been developed for the simultaneous determination of inorganic cations (Na+, NH4+, K+, Mg2+, and Ca2+) and inorganic anions (PO43−, Cl−, NO3−, and SCN−) using a single pump, a single eluent and a single detector. The method is based on column switching means allows anions and/or cations could be determined in a single analysis system. While one ion-exchange column is being operated, the other ion-exchange column is being conditioned, i.e., the columns are always ready for analysis at any time. When the combination of 10 mM tartaric acid was used as the eluent, and operated at eluent flow rate of 0.5 mL/min, five cations and four anions could be separated on the cation-exchange column and the anion-exchange column, respectively. The separation of cations was completed within 15 min, whereas the separation of anions was completed within 40 min. The detection limits was calculated at S/N = 3 were 3.10–12.14 ppb (µg/L) for the cations and 16.00–88.10 ppb for the anions. The relative standard deviations of the all ions were less than 4.81%, 6.30%, and 6.22% for peak height, peak area, and retention time, respectively. The developed technique was successfully applied to the simultaneous determination of inorganic cations and anions in human saliva and urine samples.

Simultaneous Determination of Inorganic Cations and Anions in Microchip Electrophoresis Using High-voltage Relays.

A new and simple method for the simultaneous determination of cations and anions by microchip electrophoresis with capacitively coupled contactless conductivity detection (ME-C4D) is described. The best analytical performance was found by applying a sinusoidal wave with 800 kHz frequency and 20 Vpp amplitude. An optimized background electrolyte (BGE) composed of 20 mM His/MES and 0.01 mM CTAB was chosen for the simultaneous analysis. Samples containing K+, Na+, and Li+ as the cations and Cl-, F- and PO43- as anions were analyzed simultaneously in a single run (within 3 min). The reproducibility obtained by the method was compared with those obtained in previous studies that had employed simultaneous analysis of anions and cations by ME-C4D. The proposed simultaneous determination method is inexpensive, simple, fast, easy to operate, and offers a high degree of integration.

Capillary electrophoresis – A new tool for ionic analysis of exhaled breath condensate

Exhaled breath condensate has been analyzed for its ionic content by capillary electrophoresis with capacitively coupled contactless conductometric detection. A simple device for collection of small volumes (100–200μL) of exhaled breath condensate in less than 2min was developed. A method for simultaneous determination of inorganic cations, inorganic anions and organic anions from the samples using dual-opposite end injection principle with a short fused silica capillary (35cm, 50μm I.D.) was developed. A background electrolyte composed of 20mM 2-(N-morpholino)ethanesulfonic acid, 20mM l-histidine, 30μM cetyltrimethylammonium bromide and 2mM 18-crown-6 was used. The analysis time was less than 3min with limits of detection reaching low μM levels for most of the anions and cations. It has been shown that changes of nitrite could be observed in acute inflammation of upper airways and in a person with diagnosed mild chronic obstructive pulmonary disease, while changes of other ions could also be observed. Lactate concentrations could also be monitored and about 4-fold increase of lactate concentration in exhaled breath condensate was determined following an exhaustive cycling exercise. The developed non-invasive sampling of exhaled breath condensate, followed by rapid capillary electrophoretic analysis, could be very useful in lung inflammatory disease screening as well as in monitoring fast metabolic processes such as lactate build-up and removal.

Simultaneous Determination of Inorganic Cations by Capillary Ion Chromatography with a Non-suppressed Contactless Conductivity Detector

A non-suppressed capillary ion chromatographic method with a laboratory-made packed cation-exchange column (100 mm × 0.32 mm i.d.) was developed for the separation and simultaneous determination of five common inorganic cations (sodium, ammonium, potassium, magnesium and calcium). Cation exchangers were prepared by the reaction of the hydroxyl group on the surface of diol-group bonded silica gel with 1,3-propanesultone in methanol. Simultaneous separation of these five common inorganic cations were achieved within 17 min using 1 mM methanesulfonic acid and 0.1 mM 15-crown-5 ether in methanol-water (8:2, v/v) as the eluent. The effects of organic solvents and crown ethers in the eluent on the retention of analytes were investigated. The limits of detection (S/N = 3) of the cations were in the range of 18-124 µg/l, the linear correlation coefficients were 0.9991-0.9998, and the RSD values of retention time and peak height were all smaller than 2.1%. The present analytical method was successfully applied to the rapid and direct determination of inorganic cations in samples of river water and commercial drinks, with satisfactory results.

Simultaneous Determination of Inorganic Cations and Anion in Medical Electrolytes by Capillary Electrophoresis

Capillary electrophoresis (CE) was developed in order to effect rapid, specific determination of potassium, calcium, sodium, and magnesium. Ions (4 cations, 1 anion) were measured continuously via shifting of samples from the inlet electrode to the outlet electrode; moreover, samples were subjected to indirect and direct ultraviolet (UV) techniques, respectively. For the measurement of cations, imidazole (5 mM) functioned as a UV absorber of indirect detection at 214 nm. Consequently, anions can be measured directly by UV at 214 nm. Separation times of cations and Cl− anions were 10 min and 2 min, respectively; the detection limit of each ion (chloride, magnesium, sodium, calcium, and potassium) was 0.1 µmol/L. This approach is very simple; additionally, measurement time is extremely short. As a result, the proposed method is suitable for routine assay of electrolytes in pharmaceutical preparations.

A new approach for the simultaneous determination of inorganic cations and anions using ion chromatography

A new approach for the simultaneous determination of inorganic cations and anions using ion chromatography was proposed. In this study, a zwitterionic stationary phase was employed with water as the eluent. With the ion separation achieved under these conditions, each anion species of the analytes could be separated from the others and eluted together with the analyte cations. The combination of the analyte anions with the analyte cations can be considered as an “ion-pairing-like” form and is briefly denoted as “ion pair”. If we determine all the ion pairs, the concentrations of the anions and the cations in the original solution can be calculated. This new approach for the simultaneous determination of inorganic cations and anions was investigated in this study.

Simultaneous Determination of Inorganic Cations in Cardioplegic Solution by Photometric Ion Chromatography. A Comparison with Autoanalyzer Method.

A simultaneous determination of four inorganic cations in cardioplegic solution was examined by indirect photometric ion chromatography (PIC). Cardioplegic solution was diluted 100-fold with 2.5mM copper sulfate aqueous solution, treated with SEP-PEK C18 and ACCELL PLUS QMA cartridges, and then injected into the chromatograph. Large amounts of sodium, potassium and magnesium and small amount of calcium were separated on a Zorbax SCX-300 column with 2.5mM copper sulfate solution as an eluent, and detected as negative absorption peaks by an ultraviolet (UV) photometric detector at 230 nm. Straight calibration curves for the cations were obtained from 0.05 to 1.5mM by using a peak height ratio method. The reproducibility of the data was good enough. When cardioplegic solution was diluted 4-fold with the eluent, the determination of calcium in sample solutions was sufficiently good, in spite of over-loadings of the other cations on column. The results obtained by the PIC method were more accurate than those of the autoanalyzer meth

Simultaneous determination of inorganic cations and anions in capillary zone electrophoresis (CZE) with indirect fluorescence detection

An instrumental configuration for the simultaneous determination of inorganic cations and anions in capillary zone electrophoresis (CZE) is described. The sample is injected into the central part of the capillary by hydrostatic injection. Indirect fluorescence detection is used. The electrolyte system consists of 2,5-dihydrobenzoate as fluorescent anion and cerium(III) as fluorescent cation. This method allows the analysis of both cations and anions without changing the electrolyte system in less than five minutes.