Why is a blank sample important in spectroscopic measurements?

A blank sample is important in spectroscopic measurements as it helps to calibrate the instrument and eliminate background interference.

In spectroscopic measurements, a blank sample is used as a reference point to ensure the accuracy of the results. It is essentially a sample that contains all the components of the test sample, except for the substance being analysed. This means that any reading obtained from the blank sample is due to the other components in the sample, not the substance of interest. By subtracting this reading from the test sample's reading, you can isolate the effect of the substance being analysed, thereby improving the accuracy of the results.

The blank sample is also used to calibrate the instrument. Calibration is a process that ensures the instrument is working correctly and providing accurate readings. It involves comparing the instrument's readings with a known standard or reference point. In the case of spectroscopic measurements, the blank sample serves as this reference point. By setting the instrument's reading to zero with the blank sample, you ensure that any subsequent readings are relative to this zero point. This helps to eliminate any potential bias or error in the instrument's readings.

Furthermore, the blank sample helps to eliminate background interference. Spectroscopic measurements are often affected by various forms of interference, such as stray light, electronic noise, and the absorption or emission of light by other components in the sample. These can distort the readings and lead to inaccurate results. By using a blank sample, you can measure and account for this background interference, thereby ensuring that the readings are solely due to the substance being analysed.

In conclusion, a blank sample plays a crucial role in spectroscopic measurements. It helps to calibrate the instrument, eliminate background interference, and improve the accuracy of the results. Therefore, it is an essential part of any spectroscopic analysis.