Chill all chemicals using a general purpose laboratory refrigerator set at 4 degrees Celsius. Make your fixative in an Eppendorf tube by adding 10 percent formaldehyde and 5 percent glutaraldehyde to deionized water. Mix thoroughly with your pipette.
Prepare 1N NaOH by adding 40.00 g of sodium hydroxide to laboratory distilled water to make a quantity of 1 liter. Prepare the staining solution by using a pipette to add the 1N NaOH solution to 10 microliters (ul) of 2 percent aqueous phosphotungstic acid until you have a pH of 7.3. Measure your pH using a laboratory grade pH meter.
Add 100 ul of virus suspension to an Eppendorf tube, measuring it with a pipette. Fix the virus suspension by adding 10 ul of the 10 percent formaldehyde and 5 percent glutaraldehyde fixative.
Combine in an Eppendorf tube 10 ul of virus suspension, 10 ul of latex spheres and 10 ul of distilled water containing 1 percent BSA, or bovine serum albumin. Leave out the latex spheres if you do not need to count the viruses. Pipette the solution 30 times, using gentle flow technique to avoid damaging the viruses.
Apply the solution to the electron microscope grid, and leave for 30 seconds to one minute. Use a piece of filter paper to draw extra fluid off from the side. You want a thin and even film.
Add 6 to 10 ul of the 2 percent aqueous phosphotungstic acid immediately to the microscope grid. Leave it on for 30 seconds, and then draw it off with a piece of filter paper. Ensure an even film forms while drawing off the solution.
Place the grid into the grid box, and allow the slide to air dry for several hours or overnight. Your viruses are now able to be viewed.