Milestone DMA-80 evo - 8 TIPS & TECHNIQUES; 8.2 CALIBRATION; 8.2.1 How to make a standard liquid solution

Milestone Srl MA213-003 – DMA-80 EVO – User Manual
144
8 Tips & techniques
8.1 GENERAL RULES
Before starting to work with the unit, it is necessary to eliminate any contamination coming from
environmental dust or from the samples.
Before each use, a cleaning procedure is always recommended for the metal boats - in the DMA-80 or in
a muffle - and for laboratory tools such as spatula, balance plate, tweezers, etc.
It is particularly important to follow these recommendations when working at low concentrations of Hg.
8.2 CALIBRATION
8.2.1 How to make a standard liquid solution.
The Direct Mercury Analyzer can be calibrated using solid Standard Reference Materials or diluted
aqueous standards. Diluted aqueous standards (or working standards) may be prepared by diluting either
1000 ppm or 100 ppm Hg standards (stock solutions).
Solutions must be stabilized with ultrapure HCL 2% v/v.
Both standards are commercially available. (Stock solutions on market can be stabilized with HNO3 or
HCL).
Use the equation below to dilute the standards.
Working standard (ppm) = Stock solution (ppm) x (Volume of the stock solution (mL)/Total volume
(mL)*)
* Total volume is the volume of the working standard
Example:
To prepare 1000 µg/Kg(1 ppm) working standard, take 100 µl of the 1000 ppm Stock solution and dilute
up to 100 mL.
To prepare 2000 µg/Kg(2 ppm) working standard, take 200 µl of the 1000 ppm Stock solution and dilute
up to 100 mL.
To prepare 5000 µg/Kg(5 ppm ) working standard, take 500 µl of the 1000 ppm Stock solution and dilute
up to 100 mL.
To prepare 7000 µg/Kg(7 ppm) working standard, take 700 µl of the 1000 ppm Stock solution and dilute
up to 100 mL.
To prepare 10000 µg/Kg(10 ppm) working standard, take 1000 µl of the 1000 ppm Stock solution and
dilute up to 100 mL.
The diluted aqueous standards for low and medium concentration (ppb range) can be prepared from the
1 and 5 ppm solution.
To prepare 5 µg/Kg(5ppb) working standard, take 0.5 mL of the 1 ppm solution and dilute up to 100 mL.
To prepare 10 µg/Kg(10ppb) working standard, take 1 mL of the 1 ppm solution and dilute up to 100 mL.
To prepare 20 µg/Kg(20ppb) working standard, take 2 mL of the 1 ppm solution and dilute up to 100 mL.
To prepare 30 µg/Kg(30ppb) working standard, take 3 mL of the 1 ppm solution and dilute up to 100 mL.
To prepare 50 µg/Kg(50 ppb) working standard, take 1 mL of the 5 ppm solution and dilute up to 100 mL.