Frequency: Daily
- Any spill on, or around the instrument should be cleaned immediately.
- At the end of the day, turn off the instrument or disconnect the power source or the battery terminals as appropriate.
- Keep the cuvette chamber empty and closed when not in use.
- Cover the instrument after use. Store appropriately, protected from dust.
Frequency: As needed
- Replace blown fuses and bulbs according to the manufacturer’s instructions.
- If the equipment is faulty, consult a qualified biomedical engineer.
Frequency: Every six months
- Inspect the instrument visually to verify the integrity of its components according to the manufacturer’s specific cations.
- Verify that the buttons or control switches and mechanical closures are mounted firmly and that their labels are clear.
- Ensure that all the accessories are clean and intact.
- Check the adjustment and condition of nuts, bolts and screws.
- Make sure the electrical connections do not have cracks or ruptures. Test that these are joined correctly.
- If applicable:
a. Verify that cables securing devices and terminals are free from dust, grime, or corrosion.
b. Verify that cables are not showing signs of splicing or of being worn out.
c. Examine that the grounding system (internal and external) is meeting the electric code requirements.
- Make sure the circuit switches or interrupters, fuse box, and indicators are free from dust, corrosion, and grime.
- Check lamp alignment if recommended by the manufacturer.
Frequency: Annually
These tests must be performed by an electrician or engineer and results must be recorded and archived for follow-up through time.
- Check the installation location for the safety of the electrical and physical infrastructures.
- For instruments using main power:
- a. Check that the voltage is appropriate and does not vary more than 5% from the voltage in the equipment specifications.
- b. The polarity of the outlet is correct.
- Check that there is sufficient space around the instrument for the connecting cables and for adequate ventilation.
- Test the integrity of the counter and its cleanliness.
- Verify that the instrument is away from equipment generating vibrations and direct solar radiation.
- Check that there is no excessive humidity, dust, or high temperature.
- Ensure that there is no source of smoke, gas, or corrosive emissions. This is very helpful for the maintenance of the colorimeter
Cuvette use and maintenance
Cuvettes must be rigorously clean for accurate measurements.
- Always hold cuvettes by their opaque, non-optical walls.
- Unless specified by the operator’s manual, do not perform any measurements without performing a blank determination.
- Use a single cuvette or a set of matched cuvettes for the proper performance of the instrument. Note: Absorbance of cuvettes should not exceed 0.01 when measuring distilled water. To avoid incorrect results, a cuvette exceeding this limit should not be used as part of a set unless it is matched with one with the same absorbance reading when measuring distilled water.
- Remove bubbles present in the solution by gently tapping the cuvette with the finger.
- Ensure that there is a high enough level of solution in the cuvette (above the light beam) so that the reflection of light from the surface does not interfere with the reading.
- All solutions used and the specimen to be measured should be clear. If the mixed reagent solution and specimen are turbid, the measurement must be repeated after checking and confirming the cuvette’s transparency and cleanliness.
- If a kinetic measurement is performed over a long period of time, seal the cuvette to avoid evaporation causing erroneously high readings.
- When performing readings on a series of specimens, readjust the zero every 5 to 10 measurements by reading the blank solution to avoid drift of the zero.
- Do not leave the cuvette in the instrument.
- If using semi-micro or micro-cuvettes, ensure correct positioning in the light path to avoid false readings due to partially reflected light.
- Store in a dust-free box to prevent damage as scratched or damaged cuvettes can lead to incorrect measurements.
