Recent content by tring

Thanks, - I have 9 solutions of citrate, Na, K , Cl, phosphate, oxalate, urate, magnesium, creatinine, ammonium all together, with ionic strenghts as mentioned. I know the compositions - and fit the pH knowing all the standard pks for citrate and phosphate etc. The pH was measured by the lab -...

Dear friends - I now have 9 complicated urine like fluids of phosphate, creatinine, Na, K , Cl, oxalate, urate, magnesium, citrate of computed ionic stregnths from 0.16 to 0.46 and measured pH from 3 to 9. I fit a monotone relationship without any corrections for nonideal behaviour from 2.5 to 8...

Thanks again for the answer. I had hoped you wouldn't ask me what I was trying to accomplish, but here goes. What I want to is explore the relationship between the measured strong ion difference in urine (Na+K-Cl-2*SO4 etc) and the apparent SID, had e.g. from eq 1 in the Herman and Booth...

Thanks - I found Davies also here http://www.colorado.edu/ceae/environmental/ryan/cven3454/spreadsheets/actcoeff.xls but as indicated in the complicated theory and e.g. at this site http://www.calcenstein.com/calc/0328.php I need to account for the interactions. So here is the SO4-- the...

In a urine sample (Relman JCI 1961) urine is analyzed. We have a [Na] of 132 mmol/l, K of 62.7 mmol/l, Cl of 182 mmol/l, sulfate of 21.2 mmol/l and some other minor species. The ionic strenght is about 0.22 - now I need to compute the Na+K-Cl-2*SO4. So the ionic strength is higher than 0.1, but...

Thanks a lot for the pdf. I found it very supporting of the view that given the "raw" chemistry, pH should be defined by that alone. Another matter is actually to calculate it exactly against difficulties in knowing activity coefficients, which influence both the pks and the SID as defined in...

Thanks again. You may be surprised but this fact is seemingly unknown to many in renal physiology, and at least it is unused. Might you have a single reference on the subject? With regard to the ionic strenght question, is the problem that the pks become difficult to know or is it something else?

Thanks a lot. I saw your page http://www.chembuddy.com/?left=pH-calculation&right=general-pH-calculation that you method is exactly what I have used: writing up all equations and mass balances under charge balance. Only I do not need any simplifications. Thanks a lot

I need to know whether, given the actual composition of a synthetic fluid (in water) stated as concentrations of Na, K, Cl, urea, NH4, phosphate, citrate, and creatinine a resulting pH can be computed from first principles given the involved pKs - 3 for phosphate and citrate, one for creatinine...