Waters Envirogel GPC Cleanup Column - Manual (Page 3)

[ Care and Use ManUal ]
3 Waters Envirogel GPC Cleanup Column
4. Continue the flow until a stable absorbance reading is obtained.
The columns are equilibrated when the change in the absorbance
reading is ≤ 0.002 AU from zero after 500 mL of solvent passes
through the column.
5. Read just the absorbance level to zero, if necessary
ii. CaliBrating tHe Columns
The Envirogel GPC Cleanup columns are calibrated using a
calibration solution.
Calibrating the columns involves:
• Preparing the calibration solution
• Injecting the calibration solution
• Calculating peak resolution
If you are using an injector with a 5 mL sample loop, use the calibra-
tion method listed in the EPA method.
If you are using the Waters GPC Cleanup System, use the calibration
method described in this section.
Since the Waters GPC Cleanup System performs 2 mL sample injec-
tions, you must use a calibration solution that is 2.5 times more
concentrated than the calibration solution listed in the EPA method.
A 2 mL injection of the concentrated calibration solution achieves
mass loading equal to a 5 mL injection of the EPA method calibration
solution.
a. Preparing the Calibration Solution
Mix the calibration compounds into low acid methylene chloride (pes-
ticide quality or equivalent). Refer to the Waters GPC Cleanup System
Operator’s Guide, Chapter 2 “Preparing the System” for the procedure
to determine the acid level of methylene chloride.
One liter of calibration solution requires the following quantities of
compounds:
Reduce the quantities for smaller volumes of solution.
b. Procedure
To prepare the calibration solution:
1. Weigh the Corn oil into a beaker. Since the sulfur is more soluble
in warm com oil than methylene chloride, add the sulfur to the
corn oil. Warm the mixture until the sulfur dissolves.
2. Add the remaining compounds listed in the table above to a
volumetric flask.
3. Add the warm corn oil-sulfur mixture to the volumetric flask.
4. Add methylene chloride to bring the volume of solution to one
liter.
5. Store the calibration solution away from light, at 4 ˚C, in an
amber bottle with a Teflon ® lined screw-cap. The solution can be
stored up to 6 months. After storage, allow the solution to stand
at room temperature until components redissolve.
A small amount of sulfur may precipitate from the solution when the
methylene chloride is added or after the solution is stored. Remove
this precipitate by filtering the calibration solution through a GHP
Acrodisc
® 0.45 μm filter before injection.
Compound mg/L
Corn oil 62,500
Bis(2-ethylhexyl)phthalate 2,500
Methoxychlor 500
Perylene 50
Sulfur 200