Simultaneous determination of lithium, sodium and potassium in blood serum by flame photometric flow-injection analysis

A simultaneous flow-injection analysis (FIA) manifold that could analyse three ions from a single injection was designed, constructed, calibrated and used successfully to analyse Li(+), Na(+) and K(+). This FIA method was 10 times faster than the batch technique. The sample volume required was a fraction of about 1/110 to 1/75 that of the batch technique. The outputs were quite reproducible and calibration curves were linear. Results obtained for artificial sera compared favourably with the actual known concentrations of ions and results obtained in the analysis of eight natural human blood sera compared well with those obtained by the traditional batch technique.     

Simultaneous determination of sodium, potassium, magnesium and calcium in surface, ground and domestic water by flow-injection analysis

Summary A simple, rapid, automated procedure is described for the simultaneous determination of sodium, potassium, magnesium and calcium in surface, ground and domestic water, based on the principles of the flow-injection technique in combination with flame photometry and AAS. The method is suitable for the simultaneous analysis of sodium, potassium, calcium and magnesium at a rate of up to 128 samples per hour with a coefficient of variation of better than 2.1% for sodium, 1.7% for potassium, 2.7% for calcium and 1.8% for magnesium.

---

Simultanbestimmung von Natrium, Kalium, Magnesium und Calcium in Oberflächen-, Grund- und Trinkwasser mit Hilfe des Flow-Injections-Systems

Zusammenfassung Das beschriebene automatisierte Verfahren zur einfachen und schnellen Bestimmung von Na, K, Mg und Ca in Wasser beruht auf dem Flow-Injektionsprinzip in Kombination mit Flammenphotometrie und AAS. Je Stunde können 128 Proben analysiert werden. Die Variationskoeffizienten sind < 2,1% für Na, < 1,7% für Kalium, < 2,7% für Calcium und < 1,8% für Magnesium.

     

Determination of menadione sodium bisulfite in pharmaceutical preparations by flow-injection on-line photochemical spectrofluorometry.

A flow-injection on-line photochemical spectrofluorometry (FI-PF) was developed for the determination of menadione sodium bisulfite (MSB) using acetone and sodium sulfite as sensitizing reagents. An injected sample band carried by a water stream was on-line merged with a mixed NaOH, Na2SO3 and acetone solution in a "T" connector. It was then driven to pass a knotted PTFE photochemical reactor (0.5 mm i.d. x 200 cm, KR) that was freely coiled around a 6-W low-pressure mercury lamp. While passing the KR, MSB was derived into an intensively fluorescent compound that was on-line delivered into a flow-through cell and detected therein at an emission wavelength of 459 nm and an excitation wavelength of 336 nm. Under optimized conditions a detection limit of 0.38 microg l(-1) was achieved at a sampling rate of 90 h(-1). Eleven determinations of 0.5 mg l(-1) and 0.05 mg l(-1) MSB standard solution gave RSDs of 0.75% and 1.3%, respectively. The calibration curve was linear in the MSB concentration range 0.005-1.5 mg l(-1). The proposed method was successfully applied to assay the MSB content in MSB injection.     

Determination of nitrate by flow-injection analysis with an on-line anion-exchange column

Nitrate (? 6 × 10^-4 M) is determined by displacing thiocyanate froman anion-exchange mini-column and determining it spectrophotometrically after reaction with iron (III). The efficiency of lead- and silver-loaded ion-exchange columns in removing anionic interferences is investigated. It is found necessary to incorporate a copperized cadmium reductor to reduce lead or silver ions released by these columns, which otherwise depress the nitrate response. Incorporation of a lead/silver ion-exchange column allows the determination of nitrate in tap water.     

Integrated multi-sensor chip with photocured polymer membranes containing copolymerised plasticizer for direct pH, potassium, sodium and chloride ions determination in blood serum

An analytical system based on a sensor array with ion-selective field effect transistors (ISFETs) monolithically integrated in one chip covered with photocured polymer membranes containing copolymerised plasticizer and a sequential injection analysis (SIA) is shown to offer an automation of the analysis of blood serum components. For sequential injection system a custom made dual channel flow cell for the sensor array was developed. Optimisation of ion-sensitive membrane characteristics and calibration solution compositions were carried out. The system was used to analyze sodium, potassium, chloride ion contents in blood serum samples. The precision of the ion determination in samples was typical for potentiometic method with standard deviation of about 3-5%.     

Mixed reagents in multicomponent flow-injection analysis Simultaneous determination of iron and copper in blood serum with mixed bathocuproinedisulphonate and bathophenanthrolinedisulphonate or ferrozine

Mixtures of 0.6mM bathocuproinedisulphonate (BC) and 0.2mM bathophenanthrolinedisulphonate (BP) or 2mM BC and 0.2mM ferrozine (FZ) were used for a rapid determination of iron and copper in deproteinated blood serum in the presence of 0.1M formate buffer (pH 3.5), 10mM ascorbic acid and 0.3M trichloroacetic acid, by two variants of multicomponent FIA with a diode-array detector (MC-FIA). Merging zones MC-FIA is especially suitable for the determination of 0.7-33muM Fe and 0.4-35muMCu, for Cu:Fe concentration ratios from 10:1 to 1:10and with RSD <3 or 2% for Fe or RSD <6 or 5% for Cu in artificial mixtures and deproteinated standard blood sera, respectively, and relative errors of less than 3-5%. The concentrations of both elements were calculated according to a simple computer program (ORTHO) for overdetermined systems (10 or 11 wavelengths), but evaluation at the absorption maxima for the individual chelates (at 2 or 3 wavelengths) also gave satisfactory results.     

Thermodynamics of aqueous mixtures of sodium chloride,potassium chloride,sodium sulfate,and potassium sulfate at 25°C

Aqueous solutions of sodium chloride, potassium chloride, sodium sulfate, and potassium sulfate can be mixed in six ways to give ternary mixtures. Two of these have already been studied and results are now presented for the remaining four systems: H₂O–NaCl–K₂SO₄, H₂O–Na₂SO₄–K₂SO₄, H₂O–KCl–Na₂SO₄, and H₂O–KCl–K₂SO₄.     

Simultaneous determination of silicon and phosphorus in biological standard materials with on-line column flow-injection spectrophotometry

Summary A simultaneous determination of silicon and phosphorus in biological standard materials with on-line column flow-injection spectrophotometry (FIA) is described. Biological materials are ashed, fused with a lithium carbonate-boric acid mixture, and dissolved in a hydrochloric acid solution. Interfering cations are removed by a simple cation-exchange column filtration. The acid effluent is evaporated to dryness, fused with a small amount of sodium carbonate for depolymerization, taken up in dilute EDTA solution, and analyzed for silica and phosphorus by FIA. For the simultaneous determination of these elements, TSK-gel SAX was used, and the eluent was 0.085 mol/l NaCl/0.01 mol/l NH₃/0.001 mol/l EDTA. Several standard reference materials [bovine liver (NBS), chlorella and pepperbush (NIES)] were analyzed for both elements. The results of phosphorus determination for bovine liver are in satisfactory agreement with the NBS certificated value. ICP measurements were applied to analyses of chlorella and pepperbush for silica and phosphorus. The agreement of the analytical results between FIA and ICP is satisfactory. Silica in bovine liver was determined in the present study for the first time.

---

Simultanbestimmung von Silicium und Phosphor in biologischen Standardmaterialien mit Hilfe von On-line Fließinjektions-Spektralphotometrie

     

Determination of sodium sulphate, calcium chloride and sodium chloride in gypsum plaster

Summary It has been shown that chloranilic acid and its salts can be used to determine sodium sulphate in the presence of calcium sulphate, calcium chloride in the presence of calcium sulphate, and sodium chloride in the presence of calcium chloride. The analysis is direct, the separation from non-desired components being carried out at the same time as the determination itself.One aspect of the use of chloranilic acid should be stressed, namely, that it sometimes is possible to differentiate between two salts that have the same anion but different cations, and examples have been given in this paper.     

Three component flow injection analysis with on-line dialysis. Simultaneous determination of free calcium, total calcium and total chloride in milk by flow injection analysis and on-line dialysis

Summary A fast and reliable fully automated three-component flow injection procedure for the simultaneous determination of free calcium, total calcium and total chloride in milk is described where the three components from a single sample injection (30 l milk samples) are determined at a sampling rate of 60 samples per hour. The samples are directed to three different channels by using two dialysers in series. Interferences in the determination of free calcium are eliminated by using a dialyser (first in the series) which also separates the total and free calcium. Free calcium is determined by UV/VIS spectrophotometry at 580 nm and total calcium by atomic absorption spectrometry (AAS) at 422.7 nm. Interferences from phosphates in milk in the determination of total calcium by AAS are overcome by using a nitrous oxide-acetylene flame with the necessary suppression with potassium ions. A second dialyser in series is used to eliminate interferences, especially the interference of casein, before the dialysed chloride is measured with a coated tubular chloride-selective electrode. The results obtained for the free calcium, total calcium and total chloride in milk at a sampling rate of 60 samples per hour compared well with data obtained by standard methods. With 30 l samples the relative standard deviation for milk samples having different concentrations of free calcium (110–170 mg/l free calcium), total calcium (1000–1500 mg/l total calcium) and total chloride (1000–1800 mg/l total chloride) were better than 0.37, 1.01 and 0.25, respectively.     

Simultaneous flow-injection measurement of hydroxide, chloride, hypochlorite and chlorate in Chlor-alkali cell effluents

A flow injection method is reported for the simultaneous determination of hydroxide, chloride, hypochlorite, and chlorate ions that exist in Chlor-alkali cell effluents in concentrations ranging from sub-millimolar to several molar. The hydroxide concentration is determined by the heat of neutralization of the injected sample into an acidic carrier stream and the chloride concentration is calculated from the measured conductance data. For the measurement of hypochlorite and chlorate, colorimetric iodometry is used. Iodide is oxidized to iodine by OCl(-) and ClO(3)(-) in acid solutions. While room temperature is sufficient for the reaction between OCl(-) and I(-), the reaction between ClO(3)(-) and I(-) requires an elevated temperature. The different reaction requirements are utilized to differentiate between NaOCl and NaClO(3), respectively.     

Excess gibbs energies of aqueous mixtures of sodium chloride,potassium chloride,sodium acetate,and potassium acetate at 25°C

Measurements have been made on the systems NaCl?NaOAc, NaOAc?KOAc, KCl?KOAc, NaCl?KOAc, and KCl?NaOAc. The results are consistent with binary Na?K and Cl?OAc interactions, and there is no evidence for triple-ion interaction.     

Flame spectrometric determination of sodium,potassium and calcium in blood serum by measurement of microsamples

Summary The discrete sampling flame atomic emission method described previously by Sarbeck, St. John, and Winefordner¹ has been applied to the determination of K, Na, and Ca in serum controls and in several blood serum samples (10 to 100l of blood serum per element needed). The results compare well with the control values and serum values obtained by clinically accepted methods. The percent relative standard deviation of all measurements was better than 4 %. The present method consists simply of injecting the blood serum sample (in some cases diluted with appropriate chemicals) directly into a suitable carrier solution which transported the serum plug into a H₂/N₂O flame. The resulting integrated emission signal is corrected for a blank emission signal and the amount of K, Na, or Ca in the blood serum sample is read directly on a suitable analytical curve.

---

Zusammenfassung Die kürzlich von Sarbeck, St. John und Winefordner beschriebene flammenphotometrische Atomaremissionsmethode wurde für die Bestimmung von K, Na und Ca in Kontrollseren und einigen Blutserumproben herangezogen. Pro Element werden 10 bis 100l Serum benötigt. Die Resultate stimmen mit den Kontrollwerten und mit den Ergebnissen anerkannter klinischer Methoden gut überein. Die relative Standardabweichung aller Messungen war besser als 4%. Das Verfahren besteht einfach darin, daß die Serumproben (gegebenenfalls mit geeigneten Reagenzien verdünnt) direkt in eine Trägerflüssigkeit injiziert und so in eine H₂/N₂O-Flamme eingeführt werden. Das integrierte Emissionsignal wird um einen Blindwert korrigiert und die Menge K, Na bzw. Ca in der Serumprobe direkt aus einer Eichkurve abgelesen.

---

---

This work supported by AF-AFOSR-70-1880 H.     

Determination of gatifloxacin in drug formulations,human urine,and serum samples using energy transfer chemiluminescence coupled with flow-injection analysis

A simple and sensitive method for the determination of gatifloxacin (GFLX) is developed by using flow injection analysis with potassium permanganate-sodium sulfite chemiluminescence (CL) detection based on the energy transfer from GFLX to terbium(III). Intense signal instead of the weak CL produced by potassium permanganate-sulfite-GFLX system can be observed when Tb(III) is added to the system. A narrow and intense emission band at 545 nm arising from the excited-state Tb(III) was obtained. Under the optimum conditions, a linear range was 5.0 × 10^?8 to 8.0 × 10^?6 M and the detection limit was 3.2 × 10^?9 M. The method has been successfully applied to the determination of gatifloxacin in drug formulations, urine and serum samples. There was no interference from some common excipients used in pharmaceutical preparations. The possible energy transfer mechanisms in the lanthanide complexes were discussed.     

Sandwich techniques in flow-injection analysis : Part 2. Simultaneous Determination of Iron(II) and Total Iron

Samples (1500 μl) are inserted between zones of water and ascorbic acid solution with subsequent addition of 1,10-phenanthroline at pH 5.0. The signal provides a plateau region corresponding to Fe(Il) followed by a peak corresponding to total iron. The proposed system allows up to 90 injections per hour. Linear working ranges are 0.1–9 and 0.3–12 mg l^?1 Fe(II) and total iron, with relative standard deviations of < 0.6 and 1.2%, respectively. Results obtained for various ground waters agree well with those obtained by a standard method.     

Determination of magnesium,calcium, sodium,and potassium in blood plasma samples by capillary zone electrophoresis

A capillary zone electrophoretic assay has been developed and validated for analysis of magnesium, calcium, sodium, and potassium in blood plasma samples. Optimum results were obtained with 20 mmol L⁻¹ imidazole (pH 2.8) and 0.5 mmol L⁻¹ oxalic acid containing 5% methanol, capillary temperature 25°C, applied voltage 30 kV, hydrodynamic injection time 3 s, and a poly(vinyl alcohol)-coated capillary (i.d. 50 μm, total length 64.5 cm and effective length 56 cm). Indirect detection was performed at 214 nm. Cadmium was used as internal standard. The migration times of magnesium, calcium, sodium, and potassium were 4.25, 3.79, 3.96, and 2.79 min, respectively. The method was applied to the determination of magnesium, calcium, sodium, and potassium in blood plasma samples. The results were compared with those from atomic absorption spectrophotometry and no statistically significant difference was found (P>0.05). This study was supported by the Turkish Republic, Prime Ministry State Planning Organization (Project Number: 98K121730)     

Simultaneous determination of glucose and L-lactate in rat brain by an electrochemical in vivo flow-injection system with an on-line microdialysis sampling.

An electrochemical in vivo flow-injection system with an on-line microdialysis sampling is proposed for the simultaneous monitoring of L-lactate and glucose in rat brain. In the first stage of the operation, the dialysate from the microdialysis probe is delivered to a sample loop of the six-way autoinjector by perfusing Ringer's solution for 80 s at 5 microl min(-1). In the second stage, the dialysate collected in the sample loop is automatically injected for 10 s into the flow-injection line. Injected dialysate is split into two streams and two portions pass through two channels with two different immobilized enzyme reactors (glucose oxidase and lactate oxidase immobilized reactors) to produce hydrogen peroxide from glucose and L-lactate in the dialysate. After a subsequent confluence of the streams, produced hydrogen peroxide can be detected amperometrically at a downstream poly(1,2-diaminobenzene) film-coated platinum electrode, without any interference from oxidizable species and proteins present in the dialysate. Because each channel has a different residence time, two peaks are obtained. The first peak corresponds to L-lactate and the second peak to glucose. The peak current is linearly related to the concentrations of L-lactate between 0.2 and 10 mM and glucose between 0.1 and 20 mM. The present method can be successfully applied to the simultaneous in vivo monitoring of L-lactate and glucose in rat brain. The analytical speed is 45 dialysates h(-1).     

Determination of l-phenylalanine in serum by flow-injection analysis using immobilized phenylalanine dehydrogenase and fluorimetric detection

A flow-injection system with an immobilized enzyme reactor is proposed for the determination of l-phenylalanine. Phenylalanine dehydrogenase from Rhodoccus sp. M4 was immobilized on tresylated poly (vinyl alcohol) beads (13 mum) and packed into a stainless-steel column (5 cm x 4 mm i.d.). Serum sample was deproteinized with tungstic acid and filtered through an ultrafiltration membrane. The sample solution (30 mul) was injected into the carrier stream (water). The NADH formed was detected at 465 nm (excitation at 340 nm). The calibration graph was linear for 0.9-600 mum l-phenylalanine; the detection limit was 0.3 mum. The sample throughout was 25 h(-1) without carryover. The half-life period of the immobilized enzyme was 23 days.     

Determination of gold in ore by flame atomic absorption spectrometry with flow-injection on-line sorbent extraction preconcentration

Gold in ores was determined by flame atomic absorption spectrometry following on-line preconcentration by sorbent extraction in a flow-injection system. The medium polarity adsorption resin Amberlite XAD-8 packed in a 220-μl micro-column was used to collect gold(III) from hydrochloric acid sample solutions for 40 s at 7.6 ml/min. Ethanol was used to elute the adsorbed analytes into the nebulizer. Optimization studies were made on sample loading rate, elution rate and sample acidity. Some possible interferences on the determination are discussed. A 35-fold enrichment was achieved at a sampling frequency of 60 h^?1 and with an RSD of 1.4%. The detection limit (3σ) and 2 μg l^?1. Results for gold in ore samples showed good agreement with those obtained using activated carbon adsorption preconcentration. The recoveries were 97–108%.