Page 221 - Demo

“Your Safer Source for Science” Recipes for Laboratory Solutions Recipes for Biological, Histological, and Chemical Solutions, continued
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Fehlings Solution A
Dissolve 34.6 g of copper(II) sulfate penta- hydrate in 500 mL DI water. Combine solution A and B (1:1) just before use. (test for reducing sugars and aldehydes)
Fehlings Solution B
Dissolve 125 g of potassium hydroxide and 173 g of potassium sodium tartrate tetrahy- drate in 500 mL of DI water. Combine solution A and B (1:1) just before use. (test for reducing sugars and aldehydes)
Ferroin Solution
Dissolve 0.23 g of iron(II) sulfate hepta- hydrate in 100 mL of DI water. Add 0.46-g of 1,10-phenanthroline monohydrate and stir until dissolved. (redox indicator)
Fluorescein
0.1% alcoholic: Dissolve 0.1 g of fluo- rescein in 80 mL of 95% ethyl alcohol, then dilute to 100 mL. (fluorescent pH indicator)
Formalin-Aceto-Alcohol (FAA)
Mix together 50 mL of 95% ethyl alco- hol, 2 mL of glacial acetic acid, 10 mL of 40% formaldehyde and 40 mL of DI water. (preservative for algae, also a fixative)
Fuchsin, Acid, Indicator
1% aqueous: Dissolve 1 g of acid fuchsin in 80 mL of DI water, then dilute up to 100 mL. (pH indicator)
Fuchsin, Acid, Stain
1% aqueous: Dissolve 1 g of acid fuch- sinin100mLofDIwaterand1mL of glacial acetic acid. Filter if neces- sary. (staining marine algae and small crustaceans)
Fuchsin, Basic
1% aqueous: Dissolve 1 g of basic fuchsin in 80 mL of DI water, then dilute to 100 mL. Filter if necessary. (pH indicator and biological stain)
Fuchsin, New
1% aqueous: Dissolve 1 g of new fuchsin in 80 mL of DI water, then dilute to 100 mL. Filter if necessary. (biological stain)
Gastric Juice
Dissolve 5 g pepsin, 8.75 g conc. hydrochloric acid, and 2.5 g of lactic acid in 500 mL of DI water. Dilute to 1 L and stir gently to avoid foaming. (digestive studies)
Gibberellic Acid
Dissolve 100 mg of gibberellic acid in 5.0 mL of ethyl alcohol. Dilute to 1 L with DI water. (plant growth hormone)
Guar Gum
Dissolve 0.5 to 1.0 g of guar gum in 100 mL DI water. Make fresh. (preparation of “slime”)
Hayem’s Solution
Dissolve 0.25 g of mercury (II) chlo- ride, 2.5 g of sodium sulfate, and 0.5 g of sodium chloride in 100 mL of DI water. (diluting solution for red cell counts)
Hematoxylin, Delafield’s
Dissolve 4 g of hematoxylin in 25 mL of 100% ethyl alcohol. Add 400 mL of saturated aqueous aluminum ammonium sulfate solution. Expose to light for a few days in a cotton stoppered bottle, then filter. Add 100 mL of methyl alcohol and 100 mL of glycerin. The stain must be ripened at room temperature for 2 months before use. Store in a well stoppered flask. (good general stain for non-woody plant tissue and animal tissue)
Hexamethylenediamine/Sodium Hydroxide
Dissolve 60 g of 1,6-hexamethylenedi- amine in 500 mL of DI water; add 20 g of sodium hydroxide; stir to dissolve; dilute to 1 L. (nylon demonstration)
Note: DI water denotes either distilled or deionized water.
Indigo Carmine
Dissolve 0.25 g of indigo carmine in 80 mL of 50% ethyl alcohol solution. Stir, dilute to 100 mL with 50% ethyl alcohol solution. Prepare fresh; shelf life is poor. (pH indicator)
Iodine, Tincture of
Dissolve 50 g of potassium iodide in 50 mL of DI water; add 70 g iodine; stir to dissolve then dilute to 1 L with 95% ethyl alcohol. Store in a dark bottle.
Iodine–Potassium Iodide
Dissolve 15 g of potassium iodide in 125 mL of DI water; add 3 g of iodine; stir to dissolve, then dilute to 1 L. Store in a dark bottle. (starch test)
Always store iodine solutions in PVC-coated amber, glass bottles.
Iodine Solution (0.05 M)
Dissolve 20 g of potassium iodide in 400 mL of DI water; add 13 g of iodine; stir to dissolve, then dilute to 1 L. Store in a dark bottle.
Iodine Solution, Gram’s
Dissolve 6.7 g of potassium iodide in 100 mL of DI water; add 3.3 g of iodine; stir to dissolve, then dilute to 1 L. Store in a dark bottle. (used in Gram staining procedure for bacteria)
Iodine Solution, Lugol’s
Dissolve 20 g of potassium iodide in 200 mL of DI water; add 10 g of iodine; stir to dissolve then dilute to 1 L. Store in a dark bottle. (General biological stain and vital stain stock solution, dilute 5:1 before use.)
Knop’s Solution
Add 1 g of potassium nitrate, 1 g of magnesium sulfate heptahydrate, 1 g of potassium phosphate dibasic, and 3 g of calcium nitrate tetrahydrate to 500 mL distilled water; stir then dilute to 1 L with distilled water. Shake solution before use to redissolve the calcium nitrate. Add 10 g of agar and 10 g of glucose to 500 mL of this solution for culturing algae. Only use distilled water when making this solution. (culturing algae)
Limewater
Add 25 g of calcium hydroxide to 1 liter of DI water; shake; allow the solid to settle before use. Keep container tightly closed. (detecting carbon dioxide gas)
RECIPES continued on next page.
Preparing an
Iodine Solution?
Iodine crystals are not directly soluble in water, which is why most water-based iodine solutions call for potassium iodide as an ingredient. Iodine is soluble in potassium iodide solutions.
As a general rule, start with approximately one-fourth of the final volume of water and add the required amount of potassium iodide. Once the potassium iodide has dissolved, add the iodine crystals. Stir until completely dissolved and bring the solution up to its final volume.
Generally, the more concentrated the potassium iodide solution, the more readily the iodine crystals will dissolve. Iodine solutions should be prepared in a fume hood.