Which of the following is an example of total organic carbon (TOC) measurement?

Total organic carbon (TOC) measurement is a method used to assess the amount of organic carbon present in water, which is crucial for evaluating water quality and the potential impact of organic matter on the environment and treatment processes. The objective of TOC analysis is to determine the concentration of carbon compounds that originate from organic matter.

This measurement is particularly important in wastewater treatment, as high levels of TOC can indicate the presence of biodegradable materials that may consume oxygen in water bodies, leading to adverse ecological effects. The process typically involves oxidizing the organic carbon in the sample and measuring the amount of carbon dioxide produced, which correlates to the total organic carbon content.

In contrast, testing for pH levels focuses on measuring the acidity or alkalinity of the water, which is an entirely different parameter not directly related to organic carbon measurement. Determining the concentration of harmful bacteria is associated with microbiological analysis, which assesses the presence of pathogens rather than organic carbon levels. Measuring ammonia concentrations pertains to nitrogen compounds, specifically ammonia, which is another distinct aspect of water quality analysis that does not concern organic carbon content.

Thus, quantifying carbon compounds in water aligns perfectly with the definition of TOC measurement, making it the correct and relevant choice.