Why is the display varying.?
1 - If the variation consistently in one direction this is Drift. This is caused by the instrument characteristics changing with temperature of the flame system.
Solution to this problem :
Let the Model 410 warm up with the flame alight and aspirating water for 30 minutes.
Recalibrate with standard every 30 minutes
The specification says drift no more than 2% per hour.
2 - If the variation is random (Up and Down ) this is instrument noise.
Solution to this problem:
Specification for short term drift is ± 1%
- Check the nebuliser uptake rate ( Section 7.6 in operator manual)
- Reduce sensitivity by reducing dilution ratio and reducing fine and coarse switch value.
- Do not display more than 2 significant digits
Can the Model 410 measure Calcium on biological fluids
Answer 2 :
Yes BUT; The samples must be pretreated to remove phosphate. The method is listed in the applications section Below
Why? - The Model 410 is a low temperature flame photometer and the flame has not enough energy to break the calcium phosphate bond.
How long will a cylinder of gas last
The instrument uses 440 mls gas per minute (propane)
1 mole of propane is equivalent to approx 22.4 litres gas.
Thus 1 mole would last 22.4/0.44 minutes = 51 minutes
I mole propane weighs 44 gms (C4H10)
So 7 kg cylinder lasts 7000/44 x 51 minutes = 135 hours
Question 4 :
Can the Model 410 measure Magnesium
Magnesium atoms emit light at UV wavelengths after excitation at higher energies than available from the M410 Flame.
I have replaced the Lithium filter (top) with Calcium filter but can get no response even from 20 ppm Calcium standard solution
The top position is occupied by the Sodium Filter, not Lithium, even though on the Model 410 Li is the top element printed on the front panel.
(This is because the optical path used in the flame photometer is opposite the bottom element position. So, for Na to be in the optical path, the filter holder lever must be pushed to the bottom position.)
So to replace Lithium with Ca, the bottom filter should be changed and Ca is measured when the filter holder lever is in the top position.( newer Model 410 Flame Photometers from serial # 15659 are fitted with Calcium as standard.)
Why are my results non linear when I measure Clinical samples for sodium even though I dilute the samples 200:1
Even after dilution Na is outside the its linear range
140 mmo/l is normal serum value for Na = 140 x 22.9 =3206 ppm
After 200:1 dilution it is still 16 ppm. Non-linearity starts at 10 ppm
Solution is to fit a Lineariser Sherwood Part 47829800
See Non Linearity of sodium