Chelex is a cation exchange resin ( styrene-divinylbenzene copolymer containing paired iminodiacetate ions) used for PCR analysis. Resin is regenerated in dilute acid and operates in a solution of PH 4 or higher. A 5 % suspension should have a PH between 10 and 11.
The resin strongly chelate metals and remove heme inhibitors and divalent cations. Chelex works by removing Hematin. Hematin is a PCR inhibitor. Chelex also inhibits Mg ions and other ions that affect DNA denaturation. Chelex DNA extraction produces shorter fragments of single-stranded DNA.
It is a simple single-tube process. A combination of alkaline suspension and boiling disrupts the cell membranes and releases DNA. The sample should be suspended in 5 % chelex and incubate it for 30 minutes at 56C. Then the sample is boiled for 8 minutes. This process lyses the cells and precipitates hemoglobin. Then the sample has centrifuged a portion of supernatant is used for PCR analysis. Ion exchange beads, denatured protein, and cell components will be formed at the bottom of the tube. In this procedure, no effort has is to remove cell debris and other inhibitors. This can produce low-quality results.