Making experimental solutions and buffers is a fundamental part of science and vital to research. Storage in an inadequate container could lead to degradation, contamination by leachables, loss of the solution due to breakage, and the need to repeat experiments. Thus, it is essential that the chosen container is leakproof, dependable, and comes in the right size for the application.

Most labware has traditionally been made of borosilicate glass, a fragile material prone to cracking, shattering, or chipping. Plastic labware is durable, break-resistant, and less likely to shatter, or break than traditional glass. The hectic environment of a laboratory is full of opportunities for glassware to be broken, introducing unknown liquid hazards and glass fragments into the workspace. The cost of replacing glassware, in addition to the health and safety hazards presented by broken glass, makes plastic labware a safer, cheaper container for a busy laboratory.

Bouncing back with plastics
Recently, plastic labware has replaced many glass cylinders and beakers, as well as other vessels. The greatest advantage of polymer materials is the increased tensile strength and resistance to breaking. When knocked or dropped, a plastic bottle or container tends to bounce or crack, not shatter and spread dangerous, sharp fragments. Additionally, better quality laboratory plastics have been developed to extend the life of labware, be environmentally conscious, and economically more effective.

Laboratory grade plasticware has been developed to provide a broad spectrum of resistances to pH, solvents, organic compounds, and extremes of temperature. Table 2 illustrates the range of common laboratory resins and their properties, as well as the compatibility of plastics with a broad range of common laboratory liquids. Careful selection of suitable plastic containers for scientific laboratory procedures ensures that plastic labware can safely replace glass.

Labware sterilization and cleaning holds enormous importance to prevent cross contamination and infection of cultures. Plastic labware can be cleaned using common soap and water methods to remove contaminating remnants of previous solutions; particular care should be taken with polycarbonate to use only neutral pH detergents. Applications in a microbiological or cell culture laboratory require a more rigorous cleaning and sterilization protocol. These sterilization techniques are potentially harsh on the containment vessel; therefore, care must be taken in choosing the best method for specific plastics. All of the listed plastics may be sterilized by gas diffusion methods, with many others also being suitable for radiation and autoclave methods. Additional considerations, such as the density, transparency, and permeability to atmospheric gasses should also be taken into account when selecting the appropriate resin.

Use of a solution in a biochemical or cell-based assay requires precise buffering and component concentration. Introduction of contaminating metals or particulates can significantly alter the pH of the buffer or change the activity level of a metal-ion-dependent enzyme. Therefore, it is essential that a plastic bottle be manufactured to ISO 14644-1 Class Seven Standards, with lot-to-lot testing to ensure particulate levels are below critical limits. The materials must be certified non-cytotoxic, non-pyrogenic, non-hemolytic, and sterile. Additionally, low particulate/low metals low-density polyethylene (LDPE) and fluorinated ethylene propylene (FEP) containers are also available and subject to a secondary washing and Class 10 laminar-flow double bagging process. These additional steps ensure a particulate level of <20 particles/mL and certification to below parts per billion levels of metal residue, ensuring their suitability for low level metals analysis in addition to critical solution storage.