Glassware washing techniques vary from lab to lab and can depend on the soil type inside the glassware, types of glassware and technique required by the laboratory’s standard operating procedure.
The three types of glassware washing we’ll look at are hand washing, residential dishwashers and laboratory glassware washers.
Hand WashingHand washing requires an acid or base wash, rinse or soak which can be performed in plastic tubs. This method requires appropriate disposal of both acids and bases after washing is complete. Hot, soapy water can also effectively clean soiled glassware. A final rinse in purified water or tap water usually completes the process. In most cases, hand-washing water will reach 120ºF maximum, requiring sanitization or sterilization to be done in an autoclave. For drying, the glassware can be hung on a drying rack, placed in an oven, or dried manually. This process is time consuming and sometimes requires a dedicated person to hand wash the glassware.
Automatic Residential DishwashersAutomatic residential dishwashers are another option sometimes employed when washing lab glassware. The initial investment is much less than an instrument designed for lab use and its features are not as durable or as flexible. The interior is generally plastic or stainless steel designed to handle basic food, soil and beverages, not chemicals and contaminants found in a laboratory. The baskets are designed for domestic plates, cups, bowls, glasses, pots and pans, rather than narrow neck glassware, culture tubes, flask, beakers, and other specialized glassware used daily in the laboratory. Basket inserts for lab utensils are also not available. Expect the manufacturer’s warranty to be void when used for purposes other than residential settings.
Automatic Laboratory Glassware WashersAutomatic laboratory glassware washers are designed to clean all types of lab soil, from light to heavy, and offer features and accessories for a broad range of lab glassware and contaminants. A washer with a high heat option is best for cleaning heavy and difficult to remove soil such as waxes, oil or agar. For more soluble soil, high heat is not required. If flasks, graduated cylinders and other narrow-neck glassware are to be washed, a spindle rack option should be considered.
The interior of a lab washer must be designed to prevent damage to the washer from residual exposure to basic laboratory chemicals. Stainless steel chambers withstand traces of the every day chemicals used in a laboratory. Internal components, including the detergent cup, seals, pumps and other plastic and rubber components, have been carefully chosen to withstand chemicals as well as the high heat conditions inside the washer.
Another feature usually incorporated into a laboratory glassware washer is an optional purified water rinse. If pressurized purified water is not available, a separate pump may be required. Some washers include a separate pump to introduce purified water into the chamber, eliminating the need to buy it separately.
HEPA filtered forced air drying, which traps dirt, lint and other particulate contaminants from the air, should be considered if your research is sensitive to this type of contamination. Also, an RS232 port, to communicate wash conditions to a printer or computer, is available on some models if validation is required.
Pipette inserts allow the effective washing of pipettes in various sizes. The attachment forces water and detergent deep inside the pipettes assuring cleanliness. Other inserts for specific types of glassware such as culture tubes, media plates, DNA sequencing plates, and BOD bottles are readily available.
Automatic washer detergents formulated specifically for laboratory washers can meet specific needs. There are a wide variety of detergents — phosphate-free, chlorine-free, surfactant-free and non-ionic or ionic. These detergents leave no residue on the glassware so they are safe for sensitive applications such as tissue culture or instrumental analysis. Some laboratory washers automatically dispense liquid detergent and weak acid neutralizing rinse solutions. This eliminates the need to manually fill the detergent cup and rinse dispenser before each use. Using a built-in pump, the washer automatically meters the precise amount of detergent and acidic rinse solution into the washer at the appropriate cycle.
To determine the best washing system for your lab, an analysis should be done to calculate your potential daily cost of hand-washing vs. the cost of buying and using an automatic glassware washer. Information such as the amount of time spent per day hand-washing glassware, costs of labor, electricity, water, and detergent, types of glassware and how much of it — all should be included in the analysis. Once all the costs are calculated and compared, you can decide if the purchase of an automatic glassware washer provides a logical payback and consistent results. It’s working hard or working smart.
Published with permission from Jenny Sprung, Senior Product Specialist, Labconco Corporation
Full article can be found at http://www.coleparmer.com/techinfo/techinfo.asp?htmlfile=glass-handVSmach.htm&ID=934&referred_id=5618