The SPINeasy DNA Purification Kit is designed for fast and efficient cleanup of pre-purified DNA samples contaminated with a wide range of inhibitory compounds such as those found in environmental sample (humic acid, heavy metals) as well as chemical compounds which might originate from ineffective purification procedures. Since problematic samples may contain diverse amounts of humic acid contaminant, the SPINeasy DNA Purification Kit provides two choices of binding buffers. The Buffer P1 is recommended for purification of samples with slight contamination of humic acids (light brownish color) or other PCR inhibitors. While the Buffer P1HA contains a novel and proprietary humic acid removal technology, which is recommended to process samples contaminated with considerably amount of humic substances (strong brownish color).