Laboratory Practices
Laboratory Practices
5940022LabPrac.fm Page 23
3. Invert the ampule several times to dissolve the reagent. Do not place your
finger over the broken end; the liquid will stay in the ampule when inverted.
Wipe the ampule with a lint-free cloth to remove fingerprints, etc.
4. Insert the ampule into the sample cell holder in the DR/2400
Spectrophotometer instrument and read the results directly.
Figure 5 Using AccuVac Ampuls
2.9 PermaChem
®
Pillows
To use PermaChem pillows (see Figure 6):
1. Tap the pillow on a hard surface to collect the powdered reagent in
the bottom.
2. Tear (or cut) across, holding the pillow away from your face.
3. Using two hands, push both sides toward each other to form a spout.
4. Pour the pillow contents into the sample cell and continue the procedure
according to the instructions.
Figure 6 Opening PermaChem Pillows
2.10 Sample Cells
A set of 10-mL round sample cells are shipped with the DR/2400 Portable
Spectrophotometer instrument. The same solution in both cells will give the
same absorbance (within ±0.002 Abs). The same solution in both cells should
give approximately the same absorbance. For more information, see Section
2.10.4 Matching of Sample Cells, below.
Note: 25-mL cells with the catalog number printed across the bottom cannot be used in
the DR/2400.
2.10.1 Orientation of Sample Cells
To minimize measurement variability when using a particular cell, always orient
the cell in the same manner before placing it into the cell holder. The fill marks
on the cells can be used as orientation guides for positioning the cells.
2.10.2 Care of Sample Cells
When not in use, store the sample cells in their boxes to protect them from
scratches and breakage. After use, empty and clean the cells; avoid leaving
colored solutions in the cells for extended periods of time.
1. 2. 3. 4.
2. Tear
4. Pour3. Push
1. Tap
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