Hach-Lange POLYMETRON 9245 User Manual - Manual (Page 117)

115
Section 13 Reagent Preparation
13.1 Conditioning Reagent
• Use of Diisopropylamine in the conditioning bottle is the Hach Lange recommended solution
(CAS no: 108-18-9; see
Diisopropylamine (DIPA) on page 119 for the MSDS). Other
reagents can be used but are not recommended (refer back to Conditioning reagent on
page 21 for an explanation).
• A minimum pH of 10.5 should be maintained when measured in the central well of the
measuring cell.
• Replenish the reagent every 3 months, or more frequently if necessary.
Note: Careful selection of the chemical company supplying DIPA will allow direct connection of the bottles
to the diffuser cap, avoiding the need for decanting.
The standard conditioner cap (G45 thread) fits on our bottles. An optional cap is available that
adapts wide-mouth MERCK bottles to the pH conditioner/bottle cap (see
Spare parts - In
contact with reagents or standard solution on page 109 ). These caps avoid transferring the
solution to the original DIPA bottle supplied by us. Other adapters are available on request.
13.2 Standard Solutions
The preparation of standard solutions for calibration and grab samples requires having very
clean containers and paying careful attention to avoid the risk of pollution during preparation. It
is important to rinse well all containers used in the preparation and storage of the solutions. In
addition, all volumes and quantities need to be very precise.
It is not advisable to prepare static sodium solutions of less than 50 ppb because these low
concentration solutions can quickly become contaminated, which in turn changes the
concentration.
1 g/L Na Solution
1. Rinse at least 3 times a 1L volumetric flask (“A” class) with ultra pure water. The cleanliness
of the flask is essential.
2. Put 2.543 g NaCl inside this flask and add ultra pure water almost to the line delimiting the
volume.
3. Shake the flask until the salt is dissolved and add ultra pure water the flask to the line
delimiting the final volume of 1L.
4. Shake a final time.
5. Store this solution in a plastic bottle (label & date), well rinsed beforehand with ultra pure
water.
10 ppm Na Solution
1. Rinse at least 3 times a 1L volumetric flask (“A” class) with ultra pure water. The cleanliness
of the flask is essential.
2. Measure very precisely 10 mL of the previous solution (1 g/L) with a micro-pipette or a glass
pipette (“A” class and well rinsed beforehand) and put it inside the volumetric flask.
3. Add ultra pure water to the line delimiting the final volume of 1L and shake it.
4. Before transferring into the storage canister, rinse it well with ultra pure water a first time
and with a small fraction of the 10ppm Na solution a second time.
5. Transfer to the storage canister (label & date).
CAUTION
To familiarize yourself with handling precautions, dangers and emergency procedures, always
review the MSDS (see
Material Safety Data Sheets (MSDS) on page 119 ) prior to handling
containers, reservoirs, and delivery systems that contain chemical reagents and standards.
Protective eye wear is always recommended when contact with chemicals is possible.