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Congo Red Indicator
0.1% aqueous: Dissolve 0.1 g of Congo red in 50 mL
of DI water, then dilute to 100 mL. (pH indicator)
Congo Red Stain
1% aqueous: Dissolve 1 g of Congo red in 100 mL of
DI to which a few drops of ammonium hydroxide
solution have been added. (plant tissue stain)
m-Cresol Purple
Add 26.2 mL of 0.01 M sodium hydroxide to 200 mL
of DI water. Dissolve 0.1 g of m-cresol purple in this
solution, dilute to 250 mL. Can omit NaOH if using
Na salt. (pH indicator)
Cresol Red
Add 26.2 mL of 0.01 M sodium hydroxide to 200
mL of DI water. Dissolve 0.1 g of cresol red in this
solution, dilute to 250 mL. Can omit NaOH if using
Na salt. (pH indicator)
Crystal Violet Indicator
0.02% aqueous: Dissolve 0.02 g of crystal violet
in 80 mL of DI water, then dilute to 100 mL. (pH
indicator)
Crystal Violet Stain (Gram)
Dissolve 2 g of crystal violet in 20 mL of 95% ethyl
alcohol. Dissolve 0.8 g of ammonium oxalate
monohydrate in 80 mL of DI water and then mix
with the crystal violet solution. Filter if necessary.
(used in Gram staining procedure for bacteria)
Destaining Solution
Add 70 mL glacial acetic acid to 400 mL methanol.
Dilute to 1 L with DI water. (removes stains from
polyacrylamide gels)
Dichloroindophenol
Dissolve 0.025 g of 2,6-dichloroindophenol, sodium
salt in 80 mL DI water, then dilute to 100 mL.
Prepare fresh. (indicator for Vitamin C)
Diphenylamine Reagent
Mix 1 g of diphenylamine in 100 mL glacial acetic
acid and 2.75 mL of concentrated sulfuric acid.
Store in an amber bottle at 2 °C. Warm to room
temperature before using. (DNA/RNA extractions)
EMB Agar
Suspend 36 g of EMB agar in 1 L of DI water and
heat to boiling to dissolve the solid. Sterilize for 15
min at 121 °C (15 lbs. of pressure) in an autoclave
or pressure cooker. Cool to 50–55 °C and swirl to
disperse the precipitate just prior to pouring into
sterilized culture dishes. (culture medium)
Eosin Y Indicator
1% alcoholic: Dissolve 1 g eosin Y in 80 mL 95%
ethyl alcohol, then dilute to 100 mL. Stir and filter if
necessary. (fluorescent pH indicator)
Eosin Y Stain
0.5% aqueous: Dissolve 0.5 g of eosin Y in
approximately 80 mL DI water, then dilute to 100
mL. Stir and filter if necessary. Add a few drops of
hloroform as preservative. (good cytoplasmic
stain)
SAFETY REFERENCE RECIPES FOR SOLUTIONS
See page 84 for a complete listing
of indicators and pH ranges.
Eriochrome Black T Indicator
1% alcoholic: Dissolve 1 g of eriochrome black T in
80 mL of 95% ethyl alcohol, dilute to 100 mL with
95% ethyl alcohol. (indicator for EDTA titrations)
Erythrosin B Indicator
1% alcoholic: Dissolve 1 g of erythrosin
B in 80 mL
of 95% ethyl alcohol, dilute to 100 mL with 95%
ethyl alcohol. (indicator for EDTA titrations)
Erythrosin B Stain
1% aqueous: Dissolve 0.1 g of erythrosin B in 100
mL of DI water. Stir and filter if necessary. Add
chloroform as a preservative. (biological stain)
Fast Green
Dissolve 2 g of fast green in 100 mL of DI water
containing 2 mL of glacial acetic acid. (tissue cell
staining)
Fehlings Solution A
Dissolve 34.6 g of copper(II) sulfate pentahydrate
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 tetrahydrate 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 heptahydrate
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 fluorescein 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 alcohol, 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 fuchsin in 100 mL
of DI water and 1 mL of glacial acetic acid. Filter
if necessary. (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 concentrated
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)
Note: DI water denotes either distilled or deionized water.
RECIPES continued on next page.
Recipes for Biological, Histological and Chemical Solutions, continued
Set up a Prep Room
See page 733 for a model storage/prep room diagram.
Safety Essentials
• Eyewash/Body Drench
• Spill Control and Clean-up Materials
• Fire Extinguisher
• Chemical-Resistant Gloves and Aprons
• Chemical Splash Goggles
• Telephone Available for Emergency Use
• Chemical First Aid Kit
• Good Ventilation
Equipment
• Electronic Balance
• Magnetic Stirrers
• Volumetric Flasks
• Graduated Cylinders
• Water Purification System
• Bottles
• Labels
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