Page 219 - Demo

“Your Safer Source for Science” Recipes for Laboratory Solutions Recipes for Biological, Histological, and Chemical Solutions, continued
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Benedict’s Quantitative Solution
Dissolve 18.0 g of copper (II) sulfate pentahydrate in 100 mL of DI water and set aside. Dissolve 100.0 g of sodium carbonate anhydrous, 200.0 g of sodium citrate dihydrate, and 125 g of potassium thiocyanate in 800 mL DI water. Heat, if necessary to aid dissolution of the solids. Allow the solution to cool, then transfer to a 1-L volumetric flask. Slowly, while stirring constantly, add the copper sulfate solution to the 1-L flask. Prepare a 0.1 M potassium ferrocyanide solution by dissolving 0.25 g of potassium ferrocya- nide trihydrate in 5 mL of DI water. Add to the 1-L volumetric flask, stir, then dilute to 1 L with DI water. Filter if necessary. (25 mL of this solution is reduced by 50 mg of glucose)
Bial’s Reagent (Sumner)
Add 4 drops of 10% iron(III) chloride solution to 100 mL of 6 M hydrochloric acid. Add .03 g of orcinol and stir. (test for pentoses and glycuronic acids)
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 penta- hydrate 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 in1LofDIwater.Heattoaboilwhile 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 tetrabo- rate) 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 concen- trated 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 chlo- ride, 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 listing of indicators and pH ranges.
Bromcresol Green
0.1% alcoholic: Dissolve 0.1 g of bromcre- sol green in 75 mL of ethyl alcohol, then dilute to 100 mL. (pH indicator)
Bromcresol Green
0.04% aqueous: Dissolve 0.04 g of brom- cresol green in 50 mL of DI water, then dilute to 100 mL. (pH indicator)
Bromcresol Purple
0.04% aqueous: Dissolve 0.04 g of brom- cresol purple in 50 mL of DI water, then dilute to 100 mL. (pH indicator)
Note: DI water denotes either distilled or deionized water.
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 monobasic (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.
RECIPES continued on next page.