1 Wiping method

The commonly used wipe extraction method is a two-step method, that is, after repeatedly wiping with a moistened cotton swab, then wiping with a dry cotton swab until the surface carrier is dry, and then using both swabs for DNA extraction. Some customers use Copan flocked swabs instead of conventional cotton swabs, because the flocked swabs use nylon fiber filling technology, the nylon fiber perpendicular to the substrate planted on the carrier, can accurately improve the efficiency of DNA collection and elution, with a special basket, the efficiency of nucleic acid extraction can be increased by 60% by laboratory verification, especially suitable for the extraction of trace DNA evidence.

2 Vacuum adsorption method

Vacuum adsorption method is divided into dry and wet, dry adsorption method is directly absorb the DNA evidence on the surface of the sample, collected for DNA detection; wet adsorption method is the principle of the first sterile cleaning solution sprayed on the surface of the sample under a certain pressure, and then use the vacuum adsorption effect, the liquid carrying DNA evidence collected, and the liquid and DNA evidence separate, to obtain the potential DNA evidence in the sample. Because wet adsorption uses the liquid penetration and dissolution, DNA extraction efficiency is better than the dry adsorption method, especially for porous, textile-type sample extraction effect is better.