When purchasing stock chemicals, what should be primarily indicated?

When purchasing stock chemicals, it is essential to primarily indicate the American Chemical Society (ACS) / Analytical Reagent Grade. This designation ensures that the chemicals meet certain purity standards recognized by the ACS, which is crucial for laboratory applications. Using high-purity chemicals is vital in wastewater analysis because impurities can lead to inaccurate results, affect the quality of experiments, and potentially interfere with the chemical analysis process.

While other factors like the manufacturer's brand, expiration date, and price per unit have their importance, the priority should be on the chemical's purity and grade to ensure reliable results in testing and compliance with regulatory standards. Therefore, emphasizing the ACS / Analytical Reagent Grade guarantees that the chemicals used are suitable for the specific analytical methods employed in wastewater testing.