点击图片查看大图| 型号：Minizone | 品牌：Design Scientific | 加工定制：否 |
Solution preparation is the first operation that has to be performed
for the vast majority of samples that are submitted to an analytical
laboratory. Accurate solution preparation and documentation is,
therefore, the foundation for the overall integrity of any analytical
laboratory. The Design Scientific PhasePrep System is designed specifically
for this purpose.
Automatic Internal Standard
Addition—Save Time, Reduce Costs
The most common way of obtaining high quantitative accuracy in
HPLC, GC, AA, Mass Spectrometry and other techniques is to spike
an unknown concentration of a sample with a known amount of
another substance—commonly known as an internal standard. After
the sample is analyzed, the response to the unknown concentration
is compared to the internal standard and an accurate measurement
of the concentration of the substance of interest is obtained.
The 3KDVHPrep Solution Preparation System saves labor while increasing
accuracy when preparing solutions having an internal standard.
The PhasePrep does this in five labor saving steps:
1. Operator enters the sample number and his/her initials.
2. A sample bottle is placed on the balance and the computer
records the weight.
3. Operator is prompted to add the appropriate amount of solute
to the bottle.
4. The computer calculates the exact amount of solvent required.
The solvent, with the internal standard dissolved, is added to the
sample to obtain a dilution with a typical accuracy of 0.02%.
5. The completed sample is removed and the printed sample label
is affixed to the bottle.
Gravimetric Dilution:
More Accurate than Volumetric
Solutions prepared using volumetric glassware are inherently inaccurate
because of the density change of the solvent as the laboratory
changes temperature. The magnitude of this error can be understood
by referring to Table 1. Since Borosilicate (Pyrex™) glassware changes
volume by only 0.013% over the same temperature span, the errors
caused by this volumetric change can easily be as high as 0.5%.
Modern analytical instruments can routinely measure to an accuracy
much better than 0.5%; however, in order to reach this potential, the
solutions used in these techniques must be prepared to an accuracy
three to ten times better (0.16% to 0.05%).
Why prepare solutions
gravimetrically rather
than volumetrically?
• Safety is improved because the pouring and spillage
associated with the volumetric method is reduced
dramatically or eliminated.
• The gravimetric method is inherently more accurate
than the volumetric method because the temperature
of the solvent can be ignored. The amount of
solvent contained by a volumetric flask is a function
of temperature—but the weight of the solvent is not
affected by temperature.
What are the costs of solvent
mixing & solution preparation
using the volumetric method
vs the gravimetric method
(PhasePrep II)?
• The cost of purchasing, replacing and cleaning of
volumetric glassware.
With the PhasePrep II this is replaced by the cost of
uncalibrated solvent containers.
• The cost of wasted solvent.
With the PhasePrep II, 135 ml or 653 ml of a solution
can be prepared as easily as one liter. Solvent
waste is minimized.
• The safety cost of handling solvents.
The PhasePrep II is a closed system. The exposure to
spilled solvents, broken glassware and harmful solvent
vapors is reduced.
• The cost of loosing laboratory integrity.
This is the highest cost of all. What price can be put on
mis-identifying a peak in a chromatogram because
the solvent was not mixed accurately or a mislabeled
solvent was used? The PhasePrep II prepares
mixtures to an accuracy of a few hundreths of one
percent or better—every time. A label is also printed
to document the preparation. This minimizes the cost
of re-works, non-conformance investigations and the
costly delays that could result in not shipping finished
product.
Method Selection Screen Sample Label
Method Editing Screen
Solution Preparation—Solvent Mixing
