The body maintains a very strict control over the levels of electrolytes in the
ID: 273549 • Letter: T
Question
The body maintains a very strict control over the levels of electrolytes in the blood and inside cells within the body. Typical blood levels of 135 – 146 mM sodium and 3.5 – 5.5 mM potassium have been measured whilst the internal concentrations of cells have been found to be 12 mM sodium and 140 mM potassium. Disruption of this blood ratio of sodium/potassium can be fatal.
As part of an analytical team working with the local Pathology department you were responsible for determining the potassium levels in blood plasmausing a potassium selective electrode.When the calibration data below were plotted using linear regression, a correlation coefficient, R2, of 0.9978 and a line of best fit were obtained;
y = 3.9657x + 0.4286
i. Use the sample data sets provided below to determine the blood plasma concentration of potassium in mM (RAM potassium = 39.10). The samples underwent a 25 fold dilution prior to analysis.
ii. Comment on the levels of potassium found in the two samples and the potential implications of your findings.
[K1 ppm (mgL) 0.05.0 10.0 15.0 20.0 25.0 Emission Signal 0.0194163 78Explanation / Answer
Ans i :
using the equation y = 3.9657x + 0.4286 concentration ot the potassium can be know putting value of x using tha data given for sample 1 & 2
from mg/L to mM divide the value by RAM i.e. 39.10
But it is also given that samples were diluted 25 times
Average of sample 1 = 230.8627609
Average of sample 2 = 87.2963069
Ans ii:
Level of potassium is found to be very high and above typical body levels. Sample 1 is found to very high in concentration of potassium. concentration of sample 1 is 2.6 times more than sample 1. Patients from which samples are taken they must have a kidney disorder and if they remain untreated chances of kidney failure and paralysis are high.
Sample 1 conc. In mg/L conc. In mM Sample 2 conc. In mg/L conc. In mM 83.3 330.77141 8.459626854 31.4 124.9516 3.195693 95 377.1701 9.646294118 35.7 142.0041 3.631818 87.5 347.42735 8.885609974 32.9 130.9001 3.347829 99.2 393.82604 10.07227724 37.9 150.7286 3.854952 89.7 356.15189 9.10874399 33.7 134.0727 3.428969