CLINICAL LAB SCIENEC

190
ESSENTIALS OF CLINICAL LABORATORY SCIENCE
FIGURE 8-5 Griffin beakers of glass with markings.
Source: Delmar/Cengage Learning.
smaller beakers and flasks may accommodate.
These devices are long, cylindrical tubes usually
held upright by a stable base that is substantially
wider than the vertical stem of the cylinder
itself (Figure 8-6). The cylinder is marked along
its entire length with calibration markers. These
containers do not possess the accuracy and precision
of volumetric glass and plastic vessels. They
may range in volume from 10 mL to 2000 mL
(1 L). A reasonably accurate measurement of a
24-hour urine specimen is a common use for this
instrument. Another use is for fairly large volumes
of materials that must be mixed in certain
proportions to each other.
Bottles for Storage
Specialized reagent bottles are available for storage of reagents, but reagents
should not be stored for long periods of time. Glass is preferable, and if plastic
is used, it should not be used for reagents that may interact with plastic.
Normally, only a single day’s supply of reagent is prepared for use at one time.
Low-quality glass bottles may slowly release ions into the reagents themselves.
Bottles are often of amber or brown glass to avoid the deterioration sometimes
associated with sunlight and fluorescent lights. Bottles may have various
types of closures, such as frosted glass stoppers that fit fairly tightly into the
opening, or they may have screw-on caps, preferably of a material that also
A
B
FIGURE 8-6 (A) Graduated cylinders. (B) Determining measurement in a graduated cylinder.
Source: Delmar/Cengage Learning.
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