They found traces ranging from less than one-hundredth of a microgram to more than 1,000 micrograms, or about one-30,000th of an ounce.

• 他们从这些纸币上测量出少至百分之一微克（一微克等于百万分之一克），多至1,000微克或大约3万分之一盎司的可卡因。