Chelex-100 is a chelating resin primarily composed of polystyrene divinylbenzene that is used to bind and remove metal ions from solutions. It is commonly employed in molecular Biology and biochemistry for DNA extraction, particularly from biological samples, as it helps to purify nucleic acids by sequestering contaminants such as divalent metal ions that can degrade DNA. This resin facilitates a simple and effective method for isolating DNA while minimizing enzymatic degradation.