QIAGEN Plasmid Mini Kit (25)

A plasmid DNA isolation kit from QIAGEN uses gravity-flow, anion-exchange tips for purification of transfection-grade plasmid or cosmid DNA. Designed for manual processing of a single sample per run, the Mini format takes 3–10 ml of bacterial culture when working with high-copy plasmids and is not recommended for low-copy plasmids at this scale. Each run takes 80 minutes and yields up to 20 µg of plasmid DNA, delivering material suitable for transfection, cloning, sequencing, and capillary sequencing applications. Bacterial cells are lysed under alkaline conditions; the cleared lysate is loaded onto a QIAGEN-tip where plasmid DNA selectively binds under low-salt and pH conditions. RNA, proteins, metabolites, and other low-molecular-weight impurities are removed by a medium-salt wash, and pure plasmid DNA is eluted in high-salt buffer before being concentrated and desalted by isopropanol precipitation. The system avoids the use of toxic substances such as phenol, chloroform, ethidium bromide, and CsCl, reducing hazard to both the user and the environment. The kit can be stored at room temperature (15–25°C) for up to two years.