Preventing Moisture Damage to Total Nitrogen Test Reagents in Summer

Total nitrogen determination is a fundamental procedure in water quality analysis, and the reliability of its results depends heavily on the condition of the reagents used. Common total nitrogen test reagents — including potassium persulfate, sodium hydroxide, and N-(1-naphthyl) ethylenediamine dihydrochloride — are inherently hygroscopic and highly sensitive to ambient humidity. 

During summer, when high temperatures coincide with elevated atmospheric moisture, the risk of reagent degradation due to moisture absorption increases substantially. Damp environments can cause powdered reagents to cake and clump, while liquid reagents may absorb water and stratify, impairing their solubility and reactivity and ultimately leading to inaccurate analytical results. 

Implementing systematic and effective anti-moisture measures during the summer months is therefore essential for safeguarding the integrity of total nitrogen measurements.

Controlling Storage Environment Humidity

The relative humidity of the storage environment is the most critical factor influencing reagent moisture uptake. For total nitrogen test reagents, the relative humidity should ideally be maintained between 40% and 60%, and should never exceed 80%. 

Summer air — particularly during the plum rain season or in coastal regions — often pushes laboratory humidity well beyond acceptable limits. Under such conditions, installing a dehumidifier in the reagent storage area is strongly recommended to continuously regulate indoor humidity. Reagent cabinets should be positioned away from sinks, faucets, and other water sources to prevent moisture intrusion from leaks or environmental condensation.

Placing desiccants inside reagent cabinets provides a simple yet effective supplementary measure. Common options include silica gel and calcium chloride desiccants. When using color-indicating silica gel, the change from blue to pink signals that the desiccant has reached saturation and requires replacement or oven regeneration. Desiccants should be checked and replaced regularly to ensure continuous absorption effectiveness.

Ensuring Airtight Packaging and Container Seals

The integrity of reagent packaging is the fundamental barrier against moisture ingress from ambient air. For unopened reagents, the outer packaging should be inspected for damage; any compromised packages should be immediately resealed in airtight bags. 

For opened bottled reagents, caps must be tightened promptly after each use to minimize the time reagents are exposed to air. When dispensing powdered reagents, any residue clinging to the bottle mouth should be wiped clean to prevent interference with the seal. Liquid reagents require particular attention to stopper integrity to prevent volatilization or leakage.