2658300 Mercury Reagent Set, 0.1-2.5 µg/L Hg

Mercury Reagent Set measures mercury 0.1-2.5 µg/L Hg in water, wastewater and seawater. Article 2658300 uses Cold Vapor Concentration method (10065). The product can be used to analyze 25 samples and can be evaluated using all Hach spectrophotometers except DR800, DR2000, DR3000 and PC II.

Mercury Reagent Set includes:

• HgEx Reagent A Stannous Sulfate Solution (p/n 2658825)
• HgEx Reagent B Sulfuric Acid Solution (p/n 2658949)
• HgEx Reagent C Sodium Hypochlorite Solution (p/n 2659059)
• HgEx Reagent 3 Alkaline Reagent Powder Pillows (p/n 2658448)
• HgEx Reagent 4 Indicator Powder Pillows (p/n 2658548)
• HgEx Reagent 5 Hydroxid Solution (p/n 2658636)
• HgEx Reagent 6 Complexing Reagent Powder Pillows (p/n 2658748)

Before starting analysis:

• It is required to collect 1000mL of the sample in analytically clean, glass or polyethylene terephthalate (PET) container.
• It is recommended to complete several analyses on mercury standards and blanks before the sample analysis.
• It is necessary to determine reagent blank for each new reagent lot.
• It is required to correct the testing results for the dilution caused by the volume additions.

Procedure for Hg measurement

The procedure for the mercury determination in water, wastewater and seawater consists of three phases. In the first phase, conduct the sample digestion by adding reagents and solutions and pretreating the collected sample on the magnetic stirring hot plate. In the second phase, perform cold vapor separation and preconcentration of mercury. In the third phase, conduct the colorimetric analysis by adding reagents and solutions and measuring testing results at 412 nm.

Summary of method

The sample is digested to change all the mercury in the sample to mercuric ions that turn into gas in semi-closed system. The ambient air moves the vapor into chemically-activated absorber column where the mercury vapor forms mercuric chloride. The mercuric chloride is eluted off the column and sensitive indicator is added. The instrument is zeroed at the absorbance peak of the unreacted indicator. A complexing agent is added to break the mercury. The increase in unreacted indicator causes increase in absorbance that is proportional to the mercury content.

Sample preparation

Add 10mL of concentrated hydrochloric acid in the container before collection to preserve the sample for later analysis. Store the conserved samples at the temperature between 2 °C and 6 °C for up to 6 months.