716 1-800-452-1261
Bile Salts
5% aqueous: Dissolve 5 g of bile salts in 50 mL
of DI water, dilute to 100 mL. Mix gently to avoid
foam. (digestive studies)
Bismark Brown Y
0.5% aqueous: Dissolve 0.5 g of bismark brown Y
in 50 mL of DI water, dilute to 100 mL, stir and filter
if necessary. (stain for protozoa)
Biuret Test Solution
Dissolve 2.3 g of copper(II) sulfate pentahydrate
in 230 mL of DI water. Set aside. Dissolve 308 g
sodium hydroxide in 770 mL of DI water (very
exothermic; cool vessel in an ice water bath)
and cool to room temperature. Add all the copper
sulfate solution to the sodium hydroxide solution.
Solution should be blue. (test for proteins)
Blood Agar Base Infusion
Suspend 40 g of blood agar base infusion in 1 L of
DI water. Heat to a boil while stirring vigorously.
Boil for one minute. Sterilize for 15 min at 121 °C
(15 lbs. of pressure) in an autoclave or pressure
cooker. Cool to 50–55 °C and pour into sterilized
culture dishes. (culture medium)
Borax
Add 4 g Borax (sodium borate, Na2B4O7 • 10H2O)
to 100 mL of DI water. Stir. (preparation of slime)
Borax Carmine
Dissolve 2 g of Borax (aka sodium tetraborate) in
50 mL of DI water, add 1.5 g of carmine and boil
for 30 minutes. Let cool, make up to 50 mL with
DI water, then add 50 mL of 70% ethyl alcohol.
Let stand for a few days, then filter. (good general
stain for plant and animal tissue)
Borax Methylene Blue
Heat 100 mL of DI water to 60 °C and stir in 2 g
methylene blue and 5 g Borax. Allow to cool slowly.
Solution improves with age. (connective tissue stain,
Negri bodies)
Bouin’s Fixative
Mix together 75 mL of saturated aqueous picric acid
solution, 25 mL of commercial formalin (10% formaldehyde
solution), and 5 mL of glacial acetic acid.
(plant and animal tissue fixative)
Brilliant Blue R-250
Dissolve 0.25 g of Coomassie brilliant blue R-250 in
40 mL methyl alcohol. Add 40 mL DI water, then 7
mL concentrated acetic acid. Dilute to 100 mL with
DI water. (staining proteins in polyacrylamide and
agarose gels for electrophoresis)
Brilliant Blue G-250
Dissolve 0.1 g of Coomassie brilliant blue G-250 in 25
mL methyl alcohol. Add 40 mL DI water, then 5 mL
acetic acid. Dilute to 100 mL with DI water. (staining
proteins in polyacrylamide and agarose gels for
electrophoresis)
Brilliant Cresyl Blue
Dissolve 0.85 g sodium chloride in 75 mL of DI water.
Add 1 g brilliant cresyl blue and stir to dissolve. Dilute
to 100 mL with DI water. (vital stain, general stain for
protozoa and plant cells)
Brilliant Green
1% aqueous: Dissolve 1 g of brilliant green in 50 mL of
DI water, dilute to 100 mL, stir and filter if necessary.
(stain for plant cytoplasm and pH indicator)
Bristol’s Solution
Dissolve 1 g of potassium dihydrogen phosphate, 1
g sodium nitrate, 0.3 g of magnesium sulfate, 0.1 g
calcium chloride, 0.1 g sodium chloride and a trace
of ferric chloride in 1 L of DI water. (culture of algae)
See page 59 for a complete list ing
of indicators and pH ranges.
Bromcresol Green
0.1% alcoholic: Dissolve 0.1 g of bromcresol green
in 75 mL of ethyl alcohol, then dilute to 100 mL.
(pH indicator)
Bromcresol Green
0.04% aqueous: Dissolve 0.04 g of bromcresol
green in 50 mL of DI water, then dilute to 100 mL.
(pH indicator)
Bromcresol Purple
0.04% aqueous: Dissolve 0.04 g of bromcresol
purple in 50 mL of DI water, then dilute to 100 mL.
(pH indicator)
Bromine Water
Add 1 mL of bromine to 200 mL of DI water and stir.
Keep in a tightly sealed bottle. The shelf life is poor
due to evaporation of bromine. (polar/nonpolar
solubility studies)
Bromphenol Blue
0.04% aqueous: Dissolve 0.04 g of bromphenol
blue in 50 mL of DI water, then dilute to 100 mL.
(pH indicator)
Bromthymol Blue
0.04% aqueous: Dissolve 0.04 g of bromthymol
blue in 50 mL of DI water, then dilute to 100 mL.
(pH indicator)
Carbol Fuchsin (Ziehl-Nielson)
Dissolve 1 g of basic fuchsin in 10 mL of 100%
ethyl alcohol (absolute); set aside. Dissolve 5 g of
phenol in 100 mL of DI water. Add the two solutions
together and stir. (bacterial stain, bacterial spores
and various cytoplasmic inclusions)
Carnoy’s Fluid
Mix together 10 mL glacial acetic acid, 30 mL of
chloroform and 60 mL of 100% ethyl alcohol. (fixative
for tissue used in chromosome studies)
Chlorophenol Red
0.04% aqueous: Add 23.5 mL of 0.01 M sodium
hydroxide to 226.5 mL of DI water. Dissolve 0.1 g
of chlorophenol red in this solution. (pH indicator)
Clayton Yellow
1% aqueous: Dissolve 1 g of Clayton yellow in 50
mL of DI water, then dilute to 100 mL. (pH indicator
and fluorescent dye for microscopy)
Note: DI water denotes either distilled or deionized water.
RECIPES continued on next page.
Recipes for Biological, Histological and Chemical Solutions, continued
Prepare Buffer Solutions
Buffer solutions are available from Flinn as premade solutions and ready-to-mix capsules and
envelopes. Buffers are typically mixtures of a weak acid and the salt of the acid or a weak base and
its salt. This combination is called a conjugate acid–base pair, and it will resist changes in pH upon
addition of small amounts of acid or base. Recipes for three common buffer solutions are provided.
pH 4: Dissolve 5.10 g of potassium hydrogen phthalate (KHC8H4O4) in 250 mL of DI water, add
0.50 mL of 0.10 M hydrochloric acid, then dilute to 500 mL.
pH 7: Prepare 0.10 M potassium phosphate mono basic (KH2PO4) solution by dissolving 3.40 g in
250 mL DI water. Prepare 0.20 M sodium hydroxide solution by dissolving 0.8 g in 100 mL DI
water. Mix 250 mL of the 0.10 M potassium phosphate solution and 73 mL of 0.2 M sodium
hydroxide solution, then dilute to 500 mL.
pH 10: Prepare 0.025 M sodium borate solution (Na2B4O7 • 10H2O) by dissolving 2.38 g in 250 mL of
DI water. Prepare 0.20 M sodium hydroxide solution by dissolving 0.8 g in 100 mL DI water.
Mix 250 mL of the 0.025 M sodium borate solution and 27 mL of the 0.2 M sodium hydroxide
solution, then dilute to 500 mL.