These 2ml Screw Top Plastic Autosampler Vials are made to consistent quality standards and are an excellent choice for ion Chromatography, CE, Bio-analysis, or General Chromatography when organic solvents are not needed. Minimized ionic interactions and adsorption with vial walls provide consistent results for proteins and peptides. 2ml screw top plastic autosampler vials are made of high-quality GC-tested polypropylene material. Polypropylene vials are chemically inert and suitable for most chromatography experiments, the material of choice for pH-sensitive samples, and sodium or heavy metal analyses. Plastic bottles may be used over traditional glass bottles when the content of inorganic ions must be kept to an absolute minimum.