Xylem 6-Series Multiparameter - Manual (Page 262)

Principles of Operation Section 5
YSI Incorporated Environmental Monitoring Systems Manual 5-24
PREPARATION OF DYE SOLUTIONS FOR CHECKING SENSOR DRIFT
RHODAMINE WT STANDARD SOLUTION
CAUTION: Be certain to read and follow all the safety instructions and MSDS documentation which is
supplied with the dye before proceeding. Remember that only trained personnel should handle
chemicals.
Use the following procedure to prepare a Rhodamine WT solution for use as a sensor stability check reagent.
1. Rhodamine WT dye is usually purchased in solution form and can vary somewhat in nominal
concentration. YSI uses Rhodamine WT from the supplier noted below and recommends that the user
purchase this exact item if possible. The solution is approximately 2 % in Rhodamine WT.
Fluorescent FWT Red Dye (Item 106023)
Kingscote Chemicals
3334 South Tech Blvd.
Miamisburg, OH 45342
1-800-394-0678
Fax: 937-886-9300
2. Accurately transfer 5.0 mL of the Rhodamine WT solution into a 1000 mL volumetric flask. Fill the
flask to the volumetric mark with deionized or distilled water and mix well to produce a solution that is
approximately 100 mg/L of Rhodamine WT. Transfer this standard to a glass bottle and retain it for
future use.
3. Accurately transfer 5.0 mL of the solution prepared in the above step to a 1000 mL volumetric flask and
then fill the flask to the volumetric mark with deionized or distilled water. Mix well to obtain a solution,
which is 0.5 mg/L in water (a 200:1dilution of the concentrated solution).
4. Store the concentrated standard solution produced in (2) above in a glass bottle in a refrigerator to retard
decomposition. The dilute standard prepared in the previous step should be used within 24 hours of its
preparation.
When Rhodamine standards are required in the future, perform another dilution of the concentrated
Rhodamine solution after warming it to ambient temperature. Our experience has indicated that the
concentrated solution that has been kept at cold temperatures is much more stable than the dilute solution
stored at room temperature.
It is well known that the intensity of the fluorescence of many dyes shows an inverse relationship with
temperature. The effect must also be accounted for when “calibrating” the YSI chlorophyll sensor with
Rhodamine WT. Enter the calibration value from the table below corresponding to the temperature of the
standard.
WARNING: The “Chl Tempco” factor in the Advanced|Sensor menu, MUST BE SET TO ZERO,
when calibrating with Rhodamine WT.