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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) chloride, 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
nonwoody plant tissue and animal tissue)
Hexamethylenediamine/Sodium Hydroxide
Dissolve 60 g of 1,6-hexamethylenediamine in 500
mL of DI water. Add 20 g of sodium hydroxide, stir
to dissolve and dilute to 1 L. (nylon demonstration)
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)
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 gen eral 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 dis solved,
add the iodine crys tals. Stir until completely
dissolved and bring the solution up to its final
volume.
Gen erally, the more concentrated the
potassium iodide solution, the more readily
the iodine crystals will dissolve. Iodine
solutions should be prepared in a fume hood.
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
and shake. Allow the solid to settle before use. Keep
container tightly closed. (detecting carbon dioxide
gas)
Litmus
0.5% aqueous: Dissolve 0.5 g of litmus in 80 mL
of boiling DI water. Allow solution to cool to room
temperature, dilute to 100 mL. Stir. Filter if necessary.
(pH indicator)
Malachite Green
1% aqueous: Dissolve 1 g of malachite green oxalate in
50 mL of DI water. Stir gently to prevent foaming and
dilute to 100 mL. Filter if necessary. (pH indicator, stain
for plant cytoplasm)
Methyl Cellulose
3% aqueous: Heat 100 mL of DI water to 85 °C (not
boiling), shake 3.0 g of methyl cellulose powder into
hot water and stir rapidly while cooling the solution
to 5 °C in an ice water bath. Solution is stable at room
temper a ture, but store in tightly closed containers.
(slowing down protozoa for microscopy)
Methylene Blue
1% aqueous: Dissolve 1 g of methylene blue in 75
mL of DI water, then dilute to 100 mL. (pH indicator
and stain)
Methylene Blue, Loeffler’s
Dissolve 0.3 g of methylene blue in 30 mL of 95%
ethyl alcohol. Add 0.01 g of potassium hydroxide
and 100 mL of DI water, stir and filter. (bacterial
stain)
Methyl Green
1% aqueous, acidified: Dissolve 1 g of methyl green
in 75 mL of DI water, add 1 mL of glacial acetic
acid, then dilute to 100 mL with DI water. Stir, filter
if necessary. (1% acidified aqueous solution as
a general nuclear stain, plant stain or cytoplasm
stain)
Methyl Orange
0.1% aqueous: Dissolve 0.1 g of methyl orange in 75
mL of DI water, then dilute to 100 mL. (pH indicator)
Methyl Red
0.1% alcoholic: Dissolve 0.1 g of methyl red in 75
mL 95% ethyl alcohol, then dilute to 100 mL. (pH
indicator)
Methyl Red
0.04% aqueous: Dissolve 0.1 g of methyl red in
11.8 mL of 0.02 M sodium hydroxide solution, then
dilute to 250 mL with DI water. If using Na salt, omit
NaOH. (pH indicator)
Methyl Violet 2B, Indicator
0.04% aqueous: Dissolve 0.1 g of methyl violet 2B
in 200 mL of DI water, then dilute to 250 mL. (pH
indicator)
Methyl Violet 2B, Stain
Dissolve 0.05 g of methyl violet 2B in 100 mL of
0.7% sodium chloride solution and 1 mL of 1 M
acetic acid. Stir and filter if necessary. Use 0.9%
sodium chloride solution if staining human blood
cells. (staining amphibian and human blood cells)
Methyl Violet 6B, Indicator
1% aqueous: Dissolve 1 g of methyl violet 6B in 75
mL of DI water, then dilute to 100 mL. Stir and filter
if necessary. (biological stain)
Millon Reagent
Dissolve 1 part by weight mercury in 2 parts
concentrated nitric acid; when mercury has
dissolved, add to 2 parts water; stir. Note: always
add acid to water. (test for proteins)
Molisch Reagent
Dissolve 5 g 1-naphthol in 100 mL of 95% ethyl alcohol.
(test for aldehydes, sugars and carbohydrates)
Neutral Red
Dissolve 0.1 g of neutral red in 60 mL of 95% ethyl
alcohol, then dilute to 100 mL with DI water. Stir
and filter if necessary. (pH indicator and vital stain
stock solution)
Note: DI water denotes either distilled or deionized water.
RECIPES continued on next page.
Recipes for Biological, Histological and Chemical Solutions, continued