What is the hold time for unpreserved iron and manganese samples?

The hold time for unpreserved iron and manganese samples is 48 hours because after this period, changes in the concentration of these metals can occur due to processes such as oxidation or microbial activity. These factors can significantly alter the analytical results, leading to inaccuracies in the data collected. Therefore, it is essential to analyze unpreserved samples within 48 hours to ensure that the measurements reflect the true concentration of iron and manganese in the water being tested. Maintaining this timeframe helps in adhering to regulatory standards and ensuring the integrity of water quality testing.