What instrument is commonly used to measure the absorbance of a solution?

The instrument commonly used to measure the absorbance of a solution is the spectrophotometer. This device works by passing a beam of light through a sample and measuring the intensity of light before and after it passes through the solution. The difference in light intensity allows for the determination of how much light is absorbed by the solution at specific wavelengths, following Beer-Lambert's law. This principle is key in analytical chemistry for quantifying the concentration of analytes in a solution based on their absorbance characteristics.

The spectroscopy method is especially important in various applications such as determining the concentration of colored compounds in a sample, analyzing biochemical substances, and more. Other instruments like a pH meter focus on measuring the acidity or alkalinity of a solution rather than its absorbance, a balancing scale measures mass, and electrodes are used for electrochemical measurements, not for optical properties like absorbance.