Pharmaceutical processes typically take place on the scale of gallons or liters, even tens of thousands of liters. So why would anyone worry about one little microliter? Because in some situations, deviations as small as one microliter can mean the difference between success and failure.

Modern pharmaceutical research, quality control, and testing laboratories increasingly rely on small volumes to identify drug candidates, perform toxicity screening or dosage testing, and to determine whether pharmaceutical products are within tolerance and can be released for public consumption.
    
Just how small is one microliter?
A microliter is one-millionth of a liter. The technical definition is one cubic millimeter, a tiny cube that is only one millimeter on each edge—roughly the size of a medium-sized salt crystal. Such a small object can easily escape notice by the naked eye.

Then there are the physical properties. One microliter of liquid is a very small droplet, weighing only about one one-thousandth of a gram. Left unnoticed on a laboratory countertop, a droplet this small will evaporate completely in a very short amount of time.

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