LaMotte Fresh Water Aquaculture - Manual (Page 5)

5
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
ANALYTICAL TECHNIQUE
1. Clean glassware is a must for accurate results.
Thoroughly rinse test tubes before and after
each test. Caps and stoppers should also be
cleaned after each use.
2. Use test tube caps, not your fi ngers, to cover test
tubes and fl asks during shaking or mixing.
3. When adding sample to calibrated test tube, be
sure vial is fi lled to the appropriate mark. The
bottom of the liquid (meniscus) should be level
with the desired mark. (Figure 1)
4. When dispensing reagents from bottles fi lled
with dropper plug and cap, be sure to hold
bottle vertically and gently squeeze to dispense
the appropriate number of uniform drops.
(Figure 2)
5. For those reagents to be added with the screwcap
pipet assemblies enclosed, remove polyseal cap
on bottle and replace with the screwcap pipet.
NOTE: Place the polyseal caps back on the
reagent bottles for longer periods of storage. Be
sure that both pipet assemblies and polyseal caps
are thoroughly cleaned before placing on bottles
to avoid contamination.
6. When dispensing reagents from pipets, hold
pipet vertically to assure uniform drop size. This
is extremely important when performing drop
count titrations. (Figure 3)
7. To fi ll pipets, squeeze rubber bulb and immerse
into reagent. Release bulb to fi ll. (Figure 4)
8. To accurately dispense powdered reagents with
spoon, tap spoon on edge of reagent container
to remove excess reagent. (Figure 5)
9. When performing tests that include Octa-Slide
Comparators, the comparator should be
positioned between the operator and non-direct
sunlight. This allows the light to enter through
the light-diffusing screen at the back of the
comparator for optimum color comparison.