What is commonly used to adjust the pH during the preparation of samples for chromatography?

Buffer solutions are commonly used to adjust the pH during the preparation of samples for chromatography because they maintain a stable pH throughout the process. In chromatography, the pH of the sample can significantly influence the interactions between the analytes and the stationary and mobile phases, thus affecting the separation and resolution of compounds. Buffers, which consist of a weak acid and its conjugate base (or vice versa), can resist changes in pH when small amounts of acids or bases are added. This stability is essential for ensuring consistent and reproducible results during chromatographic analysis.

In contrast, organic solvents, saline solutions, and detergent solutions typically do not provide the necessary pH stability required for optimal chromatography conditions. Organic solvents can alter the polarity of the mobile phase but do not serve to control pH directly. Saline solutions, while useful in certain contexts, are generally not effective for pH adjustment. Detergent solutions are primarily used for solubilizing membranes and proteins rather than maintaining pH. Therefore, using buffer solutions is the most effective and reliable method for pH adjustment in sample preparation for chromatography.