Keison PFP7, Operating And Service Manual, Page: 12 / 46

11 PFP7/REV C/01-08
Section 3
Analysis Preparation
3.1 Calibration standards
A comprehensive range of aqueous calibration standards is available from Jenway in both
industrial and clinical levels. These must be diluted to a suitable concentration for aspiration into
the flame (see Sections 3.3 and 4.3)
Clinical Standards (500ml) Part Code
1.00mmol/l Li 025 008
100mmol/l Na, 100mmol/l K 025 004
140mmol/l Na, 5mmol/l K 025 006
120mmol/l Na, 2mmol/l K 025 007
160mmol/l Na, 8mmol/l K 025 005
160mmol/l Na, 80mmol/l K 025 027
Industrial Standards (500ml) Part Code
1000ppm K 025 023
1000ppm Li 025 024
3000ppm Ba 025 025
1000ppm Na 025 021
1000ppm Ca 025 009
When preparing standards always observe the following:
1. Standards must always contain the constituents that are present in the samples in the
same concentration ratios; i.e. if samples are prepared in 0.05M HCl then the standards
should also contain 0.05M HCl.
2. Always ensure that the standards encompass the expected range of the sample
concentrations.
3. Standards should be prepared so as to ensure that the region in which measurements
are made coincide with the concentrations that produce the optimum performance from
the flame photometer, i.e…
•
…when measuring sodium, the top standard is ideally 10ppm,
•
…when measuring potassium, the top standard is ideally 10ppm,
•
...when measuring calcium, the top standard is ideally 100ppm,
• …when measuring barium, the top standard is ideally 1000ppm,
•
…when measuring lithium, the top standard is ideally 10ppm.
A minimum of four standards should be prepared to enable an accurate calibration
curve to be constructed.
NOTE: The blank used should contain all the constituents of the standard solutions except the
element being measured.
Since a flame photometer measures the concentration of the element itself in solution, standard
solutions prepared from the salts of sodium, potassium, lithium, calcium and barium must be
made up to contain the concentrations required in terms of the quantity of the elements.
Below are two examples of how to prepare standards of 1mg Na/100ml (10ppm Na) and 1mg
K/100ml (10ppm K).