What is the holding time for Lachat reagents and standards?
Holding time for solutions prepared following Lachat methods.
Many Lachat methods will specify how long a solution is good for within the preparation instructions. When they are not specified one can consider the following general guidelines.
- Organic chemical dissolved in water: 1 day
- Inorganic salt in water (KCl, NaOH, CuSO4) : 1 month
- Inorganic salts containing nutrients (KNO3, (NH4)2SO4): 2 days
- Stock Standards (>1ppm): 1 week
- Working Standards (<1ppm): 1 day