Biotek EL800 - Stock Solution Formulation

Liquid Testing | 115
ELx800 Operator's Manual
Stock Solution Formulation
The stock solution for Liquid Tests No. 1 and No. 2 may be formulated from the
ingredients listed below (Solution A), or by diluting a dye solution available from
BioTek (Solution B).
Solution A
Required Materials:
• Deionized (DI) water
• FD&C Yellow No. 5 dye powder (typically 90% pure)
• Tween
®
20 (polyoxyethylene (20) sorbitan monolaurate) or BioTek
wetting agent, PN 7773002
• Precision balance with readability of 0.001 g
• Weigh boat
• 1-liter volumetric flask
Preparation of Stock Solution:
1
Weigh out 0.092 gram of FD&C No. 5 yellow dye powder into a weigh
boat.
2 Rinse the contents into a 1-liter volumetric flask.
3 Add 0.5 ml of Tween 20, or 5 ml of BioTek’s wetting agent.
4 Make up to 1 liter with DI water, cap, and shake well.
 This should create a solution with an absorbance of about 2.000 when
using 200 µl in a flat-bottom microwell. The OD value will be
proportional to the volume in the well and the amount of FD&C No. 5
dye used. You can use a larger or smaller well volume, or add more
dye or water to adjust the solution. Note that too small a well volume
may result in increased pipetting-related errors.