Good Analytical Technique
Clean glassware is a must for accurate results. Thoroughly rinse test tubes before and after each use. Caps and stoppers should also be cleaned after each use.
- When adding sample to calibrated test tubes, be sure tube is filled to the appropriate mark. The bottom of the liquid (meniscus) should be level with the desired mark (See Figure 1).
- When dispensing reagents from bottles fitted with dropper plug and cap, be sure to hold bottle vertically and gently squeeze to dispense the appropriate number of uniform drops (See Figure 2).
- For those reagents to be added with the enclosed screwcap pipet assemblies, remove polyseal cap on bottle and replace with the screwcap pipet.
- Note: We recommend placing the polyseal caps back on the reagent bottles for longer periods of storage. Be sure that both pipet assemblies and polyseal caps are thoroughly clean before placing on the bottles to avoid contamination.
- When dispensing reagents from pipets, hold pipet vertically to assure uniform drop size (Figure 3).
- To fill pipets, squeeze rubber bulb and immerse into reagent. Release bulb to fill (Figure 4).
- To accurately dispense powdered reagents with spoon, tap spoon on vial to remove excess reagent (Figure 5).
- When performing visual colorimetric tests, 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.
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Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
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