What is the preservation/analysis timing for Nitrate?

What is the preservation/analysis timing for Nitrate?

• A. Analyze ASAP, Cool <=6C; 48H
• B. Analyze in 7 days
• C. Acidify to pH<2; Cool <=6C; 7 days
• D. No preservation required

Answer: (A)

Nitrate in water samples is best kept stable by cooling and analyzing soon after collection. The primary concern is slowing biological activity that could alter nitrate levels before measurement. Keeping the sample at 0–6°C and performing the analysis within 48 hours minimizes any changes from microbial processes or other reactions, ensuring the result reflects the original sample. Acidifying to pH below 2 is not the standard preservation method for nitrate and can interfere with some measurement methods, and waiting seven days increases the risk of changes. So, the recommended practice is to analyze as soon as possible with refrigeration, within 48 hours.

Nitrate in water samples is best kept stable by cooling and analyzing soon after collection. The primary concern is slowing biological activity that could alter nitrate levels before measurement. Keeping the sample at 0–6°C and performing the analysis within 48 hours minimizes any changes from microbial processes or other reactions, ensuring the result reflects the original sample. Acidifying to pH below 2 is not the standard preservation method for nitrate and can interfere with some measurement methods, and waiting seven days increases the risk of changes. So, the recommended practice is to analyze as soon as possible with refrigeration, within 48 hours.