Use of Care of the Instrument in Soil Testing Lab
Care of Instrument:
Dust is harmful to electronic circuit, keep instrument tightly covered when not in use. Moisture is severe enemy of electric circuits. During period of high humidity, instruments should be turned daily, even if no analysis is performed. They must be enclosed in a plastic case with a 40 to 60 watt electric bulb burning to reduce humidity or enclosed with an open bottle of fused calcium chloride or similar dehydrating agent.
If chemical solutions are spilled on an instrument, when a test tube breaks in a calorimeter turn the instrument off and wash immediately and thoroughly with distilled water.
Equipment Maintenance:
An instrument that is not functioning properly will result in wither enormous results or no results at all. Proper equipments is essential to avoid or at lest mainmast such difficulties. Check your instrument regularly. Establish and follow a rigorous maintenance schedule.
Conductivity Bridge:
Conductivity bridge ordinarily do not require repairs. When difficulty is encouraged the defects often lies with the conductivity cells. Periodically inspection of the cells for the following and necessary corrections or replacement of the cell should normally take care of most of the troubles.
Photo Electro Colorimeter:
Problems:
The loose contact, burnt lamp, loose connection in photo cell, fluctuations in voltage defective photo cells are some of the cause of fluctuating readings.
Remedy:
To loose contact the burnt bulb or stabilizing voltage with the use voltage stabilizer can be done by following instructions. For measure internal defects, get instrument serviced.
Points to be remembered in making colourimeter measurements :
1. Use matched test tube
2. Observe cleanliness scrupulously
3. Do not handle the lower half portion of test solution before taking measurement
4. Always rinse the test tube with the portions of test solution before taking measurement.
5. Avoid scratching of the test tubes especially on the lower half of the test tube.
6. For accurate work a std, curve should be checked if necessary.
Flame Photometer:
For more accurate readings on flame photometer following may be kept in mind.
1. Std curve should be drawn at ease time
2. Run distilled water before and after testing each solution.
3. Do not use concentrated solution.
4. Do not light flame when the optical filter is not in position. Also do not change the filter when the flame is on.
5. Turbid extracts or solution should not be used.
6. Add few dop drops of isobutyl alcohol to improve the spray ability of the sample solution or extract.
Problems:
Unsteady flame, jumping flame, and flame blows off, blocking of suction capillary tube and atomize folts in electric controls, loose contact etc.
Remedies:
Use new gas cylinder with adequate pressure, suction capillaries be cleaned , loose contact be checked.