Potentiometric measurements of ionized calcium in anaerobic whole blood, plasma, and serum evaluated.

1985 ◽  
Vol 31 (6) ◽  
pp. 856-860 ◽  
Author(s):  
J Wandrup ◽  
J Kvetny
Keyword(s):  
Whole Blood ◽  
Volume Fraction ◽  
Salt Bridge ◽  
Sodium Formate ◽  
Ionized Calcium ◽  
Liquid Junction ◽  
Paired Samples ◽  
Significant Difference ◽  
Junction Potential ◽  
Venous Plasma

Abstract The measurements of ionized calcium and pH in paired samples of anaerobic capillary whole blood, venous whole blood, venous plasma, and venous serum have been evaluated with a modified ICA 1 analyzer and compared with those of an unmodified ICA 1 analyzer. The unmodified instrument showed a significant difference between measurements in anaerobic venous whole blood, venous plasma, and venous serum, but the modified instrument did not. Statistically significant differences between the two instruments were found for whole blood (magnitude of mean difference magnitude of = 0.053 mmol/L) and for venous serum (0.016 mmol/L), but not for venous plasma. The error of residual liquid junction potential due to blood cells, previously found in the unmodified ICA 1 (salt bridge: KCl, 2.68 mol/kg) was eliminated and independent of the erythrocyte volume fraction in the modified ICA 1 (salt bridge: sodium formate, 4.56 mol/kg). From studies of procedures for measurements of ionized calcium in anaerobically handled samples, we recommend the use of anaerobic whole blood for measuring ionized calcium.

Direct potentiometric measurement of sodium and potassium in whole blood.

1977 ◽  
Vol 23 (10) ◽  
pp. 1912-1916 ◽  
Author(s):  
J H Ladenson
Keyword(s):  
Whole Blood ◽  
Potassium Concentration ◽  
Residual Liquid ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Significant Difference ◽  
Potentiometric Measurement ◽  
Capillary Liquid ◽  
Sodium And Potassium ◽  
Junction Potential

Abstract I compared results for sodium and potassium in whole blood and plasma as measured with a newly available potentiometric analyzer, the "Orion SS-30". No significant difference was found for either sodium or potassium in 207 such comparisons. With use of the flowing, high mixing-velocity liquid junction of the Orion SS-30, the residual liquid junction potential due to blood cells was found to be less than 0.1 mV and to be independent of the hematocrit. This is in contrast to the hematocrit-dependent residual liquid junction potential of approximately 0.6 mV noted by others at normal hematocrit values with the open capillary liquid junctions now commonly used in pH instruments. I also found that the potassium concentration can increase significantly during the mixing of whole blood, and such samples should be mixed gently, if at all. Evidently sodium and potassium can be accutately and easily measured directly in heparinized blood.

Determination of sodium and potassium with ion-selective electrodes.

1984 ◽  
Vol 30 (3) ◽  
pp. 433-436 ◽  
Author(s):  
N Fogh-Andersen ◽  
P D Wimberley ◽  
J Thode ◽  
O Siggaard-Andersen
Keyword(s):  
Whole Blood ◽  
Venous Blood ◽  
Ion Selective Electrodes ◽  
Liquid Junction ◽  
Sample Handling ◽  
Blood Ph ◽  
Ionic Binding ◽  
Sodium And Potassium ◽  
Junction Potential

Abstract We compared different sample-handling techniques for measurement of Na+ and K+ with ion-selective electrodes (ISE). Imprecision was less for venous blood (with a minimum of heparin) than for plasma, serum, or capillary blood. The results for K+ were higher for serum than for whole blood, and higher for whole blood than for plasma. The latter difference was apparently due to release of K+ during the analysis. Values were more stable for whole blood stored at 20 degrees C than at 4 degrees C or 37 degrees C. The molality of Na+ in the plasma of mixed whole blood changed by -10.5 mmol/kg per unit change in blood pH. This could be explained by the different H+ buffering capacities of plasma and erythrocyte fluid, because when the pH is changed, the concentration of small anions in erythrocytes changes more than it does in plasma, with a consequent osmotic movement of water across the erythrocyte membrane. When we took into account the residual liquid-junction potential and the mass concentration of water in each of 65 patients' sera, the molality determined for Na+ was 1% lower and that of K+ 3% lower by ISE than by flame photometry--differences that may be related to ionic binding or to a lower molal activity coefficient in serum than in the calibrator.

Estimation of transfer activity coefficients for single ions between dipolar aprotic solvents from the E.M.F. of cells with liquid junction

1983 ◽  
Vol 36 (9) ◽  
pp. 1767 ◽  
Author(s):  
SS Goldberg ◽  
O Popovych
Keyword(s):  
Activity Coefficients ◽  
Salt Bridge ◽  
Aprotic Solvents ◽  
Liquid Junction ◽  
Transfer Activity ◽  
Novel Method ◽  
Glass Electrodes ◽  
Tetraethylammonium Perchlorate ◽  
Dipolar Aprotic Solvents ◽  
Junction Potential

Transfer activity coefficients for the sodium ion, logmγNa, between pairs of dipolar aprotic solvents were estimated from the e.m.f. of cells consisting of two sodium-selective electrodes in different solvents connected by a salt-bridge of triisoamylbutylammonium tetraphenylborate [(tab+)BPh4-], or tetraethylammonium picrate (Et4NPic), or tetraethylammonium perchlorate (Et4NclO4). The solvents were: acetonitrile (MeCN), N,N-dimethylformamide (HCONMe2), dimethyl sulfoxide (Me2SO), propylene carbonate (pcar), and N-methylformamide (HCONHMe). Values of logmγNA were estimated first by neglecting the liquid-junction potential E, and then, for some systems, by applying an Ej correction from theory. A novel method of estimating transfer activity coefficients for single ions, based on the Ej equation, was demonstrated on the (tab+) and Pic-ions. Transfer activity coefficients for the hydrogen ion between MeCN and HCONMe2 as well as MeCN and Me2SO were similarly estimated from the e.m.f. of two pH (glass) electrodes immersed in buffer media in the above pairs of solvents.

scholarly journals An Isotonic Potassium Chloride Liquid Junction Minimises the Effects of Ionic Strength, Protein and Haematocrit on Ionised Calcium Measurement

1988 ◽  
Vol 25 (3) ◽  
pp. 228-232 ◽  
Author(s):  
R B Payne
Keyword(s):  
Ionic Strength ◽  
Potassium Chloride ◽  
Calcium Concentration ◽  
Reference Electrode ◽  
Sodium Formate ◽  
Liquid Junction ◽  
Ionised Calcium ◽  
Isotonic Sodium Chloride ◽  
Calcium Measurement ◽  
Junction Potential

When the reference electrode liquid junction of a Nova 2 analyser was changed to isotonic potassium chloride, increasing the ionic strength of aqueous solutions containing a constant total calcium concentration had a negligible effect on measured ionised calcium. In contrast, measurements using hypertonic potassium chloride, hypertonic sodium formate and isotonic sodium chloride liquid junctions showed significant sample ionic strength effects. Interferences by sample protein concentration and haematocrit were marked with hypertonic, but negligible with isotonic junctions. Ionised calcium values in samples containing 25 mmol/L acetate, bicarbonate, β-hydroxybutyrate, lactate or pyruvate were all lower by 6–7% with an isotonic than a hypertonic potassium chloride junction. Thus, anions that replace bicarbonate during metabolic acidosis have a similar effect on residual liquid junction potential. The clinical usefulness of an isotonic potassium chloride liquid junction needs to be evaluated.

scholarly journals The Interchangeability of Plasma and Whole Blood Metal Ion Measurement in the Monitoring of Metal on Metal Hips

Arthritis ◽  
2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ibrahim A. Malek ◽  
Joanne Rogers ◽  
Amanda Christina King ◽  
Juliet Clutton ◽  
Daniel Winson ◽  
...  
Keyword(s):  
Whole Blood ◽  
Inductively Coupled Plasma ◽  
Metal Ion ◽  
Blood Concentrations ◽  
Inductively Coupled ◽  
Paired Samples ◽  
Significant Difference ◽  
Plasma Mass Spectrometry ◽  
The Mean ◽  
High Concentrations

One hundred and twenty six paired samples of plasma and whole blood were measured with inductively coupled plasma mass spectrometry technique for metal ions analysis to determine a relationship between them. There was a significant difference between the mean plasma and whole blood concentrations of both cobalt (Co) and chromium (Cr) (p<0.0001 for both Co and Cr). The mean ratio between plasma and whole blood Cr and Co was 1.56 (range: 0.39–3.85) and 1.54 (range: 0.64–18.26), respectively, but Bland and Altman analysis illustrated that this relationship was not universal throughout the range of concentrations. There was higher variability at high concentrations for both ions. We conclude that both these concentrations should not be used interchangeably and conversion factors are unreliable due to concentration dependent variability.

A New Method for the Estimation of Transfer Activity Coefficients of Ions From the E.M.F. of Cells With Liquid Junction

1988 ◽  
Vol 41 (10) ◽  
pp. 1523 ◽  
Author(s):  
A Berne ◽  
O Popovych
Keyword(s):  
Concentration Dependence ◽  
Activity Coefficients ◽  
Salt Bridge ◽  
Liquid Junction ◽  
Transfer Activity ◽  
Liquid Junction Potentials ◽  
Solvent Component ◽  
Calculated Liquid ◽  
Dipolar Aprotic Solvents ◽  
Junction Potential

Transfer activity coefficients of the tetraalkylammonium ions, logmγR, where R+ = Me4N+, Et4N+, Pr4N+ and Bu4N+, and of the picrate ion, logmγPic, between pairs of dipolar aprotic solvents, S1 → S2, were evaluated by combining the e.m.f . of cells Ag(cryst.)|AgClO4|RX|AgClO4|Ag( cryst .)�������������������������������� S1 ������ S2with the calculated liquid-junction potentials, Ej. The salt-bridge electrolyte RX was RClO4 and R Pic for the determinations of logmγR and logmγPic, respectively, and the solvents were: acetonitrile ( MeCN ), N,N- dimethylformamide (HCONMe2), dimethyl sulfoxide (Me2SO) and propylene carbonate ( pcar ). The logmγR values showed a systematic variation with the AgClO4 concentration, apparently caused by the concentration dependence of the solvent component of the liquid-junction potential, Ej,s, neglected in the calculations. However, the above concentration dependence was virtually eliminated from the values of logmγPic when they were calculated with the aid of our concentration-dependent logmγR data. For a number of our cells it was possible to evaluate the Ej,s, with the aid of literature data. The solvent component of Ej was found to be appreciable and varied both with the AgClO4 and the RX concentration. The Ej,s, was particularly large for cells containing pcar , with a maximum of -172 mV for the pcar | MeCN junction.

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