Ultra micro spectrophotometers are widely used in fields such as biomedicine and environmental monitoring due to their high sensitivity and micro detection capability. However, measurement errors may affect the accuracy of the results. The following provides practical guidelines from two aspects: error sources and avoidance methods.
Error source:
Sample factor: Insufficient purity or presence of impurity particles in the sample can interfere with the optical path, resulting in absorbance deviation; The concentration exceeds the linear range of the instrument, and being too high or too low affects the measurement; Poor sample stability, such as easy degradation under light and high temperature, can also introduce errors.
Instrument factors: poor stability of the light source, poor performance of the monochromator (such as low wavelength accuracy and wide bandwidth), and high detector noise can all reduce measurement accuracy; The cleanliness of the colorimetric dish is insufficient or the optical surface is scratched, which affects the transmittance.
Operational factors: Inaccurate sample addition, such as the need for ultra trace instruments to be precise to the microliter level, errors may lead to result deviations; Inaccurate placement or poor contact of the sample pool affects measurement; Failure to calibrate instruments regularly resulted in systematic deviations.
Environmental factors: Temperature and humidity fluctuations affect the performance of optical components in instruments; Strong light or vibration interference can affect measurement stability.
Avoidance methods:
Sample processing: Use high-quality reagents and solvents to remove impurities through filtration or centrifugation; Accurately control the sample concentration to avoid exceeding the linear range; Reduce sample exposure time and adopt storage measures such as avoiding light and refrigeration.
Instrument maintenance: Regularly calibrate the instrument and verify the accuracy of wavelength and absorbance using standard solutions; Clean the colorimetric dish to avoid scratching the optical surface; Keep the optical components of the instrument clean and regularly thoroughly clean the testing base.
Standardized operation: Use high-precision pipetting tools to ensure accurate sample addition; Correctly place the sample pool and avoid moving the instrument or sample pool; Record detailed experimental data, take the average of multiple measurements, and improve data reliability.
Environmental control: Place the instrument in a stable environment, avoiding direct sunlight, high temperature, or high humidity; Use shock-absorbing platforms to reduce vibration interference.