Which method is typically used for determining the concentration of nitrates in water?

The correct method for determining the concentration of nitrates in water is ion chromatography. This technique is particularly effective because it allows for the separation of different ions in a water sample based on their charge and size. In the case of nitrates, which are negatively charged ions (anions), ion chromatography is capable of accurately measuring their concentration as they interact with the stationary phase of the chromatographic system.

During the analysis, a sample is passed through a column filled with resin, where ions in the sample are separated. The nitrate ions are detected as they elute from the column and are quantified. This method is favored for its sensitivity and ability to analyze complex mixtures containing multiple anions, making it the preferred choice for nitrate analysis in environmental water samples.

Other methods, although useful in some contexts, have limitations when it comes to nitrate analysis. Spectrophotometry can determine nitrates but typically requires prior conversion to another form, which may introduce additional steps and potential errors. Chemical titration can also measure nitrates but is often less precise and more time-consuming compared to ion chromatography. Gas chromatography is generally not applicable for nitrates since it is more suited for volatile compounds rather than ionic species in aqueous solutions. Thus, ion chromatography stands out as the most