I. Handling Test Reagents

1. Examine carefully the label of any unknown samples and reagent bottle before using or adding the unknown or the reagent, in order to avoid using the wrong substance/reagent.
2. Keep all reagents free from contamination
3. Always use clean dropper to withdraw reagent from reagent bottle
4. When transferring a liquid reagent with a reagent dropper, always hold the dropper just above the mouth of the test tube and allow the reagent to "drop" into the test tube
5. Do not leave the reagent dropper on the bench and allow the tip of the dropper to touch the sample or anything else besides the reagent itself
6. Do not place any contaminated dropper back into reagent bottles
7. When adding reagent, always add dropwise first, observe, then shake
8. Add drop by drop first; then to excess (unless otherwise specified)
9. Always 'shake' or stir mixture well to ensure complete reaction
10. Observe and record changes e.g. colour change/precipitate formed
11. When effervescence occurs, test for gas evolved. You may need to redo experiment if gas has escaped before you can test for it.

Prev     1     2     3     4     5     6     Next