What is the role of a reference sample in spectroscopy?

In spectroscopy, a reference sample is used to calibrate the instrument and correct for background signals.

In more detail, spectroscopy is a technique used to study the interaction between matter and electromagnetic radiation. It's a fundamental tool in chemistry, used to identify and quantify the substances present in a sample. However, the accuracy of the results depends on the correct calibration of the spectroscopic instrument, and this is where the reference sample comes into play.

The reference sample, also known as a blank or a standard, is a sample that contains all the components of the test sample except for the substance to be measured. It's used to set a baseline or 'zero point' against which the test sample can be compared. This helps to eliminate any background signals or interferences that might be present in the instrument or the sample matrix, ensuring that any signal detected is due to the substance of interest.

For example, in UV-Visible spectroscopy, a reference sample might be a solution of the solvent used to dissolve the test sample. This would correct for any absorption of light by the solvent itself, allowing the absorption due to the solute to be accurately measured. Similarly, in atomic absorption spectroscopy, a reference sample might be a solution of all the matrix components without the analyte, to correct for any absorption by the matrix.

In addition to correcting for background signals, the reference sample can also be used to calibrate the instrument. This involves measuring the response of the instrument to known concentrations of the substance to be measured, and using this to create a calibration curve. The response of the test sample can then be compared to this curve to determine its concentration.

To further understand how these calibrations aid in enhancing the accuracy of spectroscopic results, you can read about the basics of collision theory, which elucidates the underlying principles influencing molecular interactions in such settings.

Moreover, the concept of energy profiles can also be explored to comprehend how energy variations within a system contribute to the spectra observed in different types of spectroscopy.

In conclusion, the reference sample plays a crucial role in spectroscopy, ensuring the accuracy and reliability of the results. Without it, it would be impossible to distinguish the signal of the substance of interest from background signals, or to accurately quantify its concentration.