How are the Standard Solutions ppm calculations derived in the manual for Radiometer Analytical ISE25Cu-9 Copper Ion Selective Electrode (ISE) (half-cell, screw cap)?

Dokument-ID

Dokument-ID TE7322

Veröffentlichungsdatum

Veröffentlichungsdatum 28.09.2018
Frage
How are the Standard Solutions ppm calculations derived in the manual for Radiometer Analytical ISE25Cu-9 Copper Ion Selective Electrode (ISE) (half-cell, screw cap)?
Zusammenfassung
Standard solutions ppm calculations Radiometer Analytical ISE25Cu-9 Copper Ion Selective Electrode (ISE) (half-cell, screw cap)
Antwort
The Standard Solutions ppm (parts per million) calculations are found in the  manual   for the Radiometer Analytical ISE25Cu-9 Copper Ion Selective Electrode (ISE) - half-cell, screw cap (Product # E41M006) on page 9.

Assuming row 1 of the table is accurate. 1 M Cu(NO 3) 2 is 5.411*10 4 Cu. That is a 5.41(10 4) Cu/kg solution.
 
A 1.0 L solution would contain 1.0 moles of Cu or 63.54 g Cu.
 
Based on the above information:
  • 1 L weighs 1,174.5 g and contains 63,540 mg Cu
  • 100 mL weighs 117.45 g and contains 6,354.0 mg Cu
  • 10 mL weighs 11.745 g and contains 635.40 mg Cu
  • 1 mL weighs 1.1745 g and contains 63.540 mg Cu
  • .1 mL weighs 0.11745 g and contains 6.354 mg Cu 
 
A 10 fold dilution (0.1 M) would be 100 mL of 1 M and 900 mL of water
  
Assuming density = 1.0 g/mL
6,354 mg Cu/(117.45 g + 900 g) = 6,354 mg Cu/1017.45 g = 6.245*10 3

Assuming density = .9982 g/mL
6,354 mg Cu/(117.45 g + 898.38 g) = 6,354 mg Cu/1015.83 g = 6.254*10 3

A 10,000 Diltuion (.0001M) = .1 mL of 1 M and 999.9 mL of water
  
6.354 mg/(0.11745 g + 999.9 g) = 6.354 mg/1000.01745 g = 6.354 ppm
  
These calculations get us close enough to see what is going on.
The density of solution (for ppm calculations) starts at .174 and approaches 0.9982 as dilution increases.
 
This shows that column 3, rows 4 & 5 are a misprint.
 
Column 3 (ppm) Row 4 (10-3) should be 6.37*10 1
Column 3 (ppm) Row 5 (10-4) should be 6.37*10 0

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