But what if a chemist needs to boil some chemical brew? Enter Pyrex, a borosilicate glass that can be taken from hot to cold extremes without breaking.
And what about the researcher who needs hundreds of small vials, and doesn't want to spend the time or money to wash them between uses? Enter plastic--a material both cheap and disposable.
And then there's the scientist who needs a beaker made of something as inert as possible. Behold Teflon, a polymer that reacts with very few substances.
These are just a few of the rapidly expanding choices available in glassware and plasticware for scientific labs. Glass is a few millennia older than plastic, but both materials have distinct advantages. And as advances in glass and plastic technology continue, neither material seems in danger of becoming obsolete in the near future.
The oldest known glass objects are beads from Egypt that were made around 2600 B.C. While no 4,000-year-old beakers are on record, today's pieces of laboratory glassware, with proper care, could become museum pieces--or perhaps even still be in use--in the year 2600 A.D.
In recent history, new plastics have pushed their way into the formerly glass-dominated domain of labware. In addition, automation has reduced the role of glassware in many labs. But the glass industry has responded to market changes and is not ready to be pushed out of the lab for good.
Reusable glassware hasn't changed much over the years, according to Andrew LaGrotte, group marketing manager at Schott America Glass & Scientific Products Inc. of Yonkers, N.Y. "Whoever invented the basic shapes had some foresight, because these shapes are still used today," he says. Scientists generally choose their labware according to specific applications and personal preference. "The very basic vessel used in the laboratory today, the beaker, is available in a wide range of materials," says John Babashak of Wheaton Scientific, based in Millville, N.J. Chemists can choose beakers made of a borosilicate glass such as Pyrex, plastic, or even platinum, depending on the amount of heat and chemical resistance needed. Even beakers made of paper are available, for paint chemists.
But overall, scientists' need for glassware has been reduced with the introduction of unbreakable or single- use disposable plastic items, says Douglas Nicoll, vice president for technical services at Bellco Glass Inc. of Vineland, N.J. "This is especially true with commodity [standard] items like tubes, beakers, Erlenmeyer flasks, and pipettes."
An obvious disadvantage of glass when compared to plastic is its tendency to break. "People are careful during use not to break glass, as this might expose them to a hazardous situation, such as toxic agents, carcinogens, radioactive or biological hazards," says Nicoll. This care does not necessarily extend to other aspects of labwork, however. "By and far, the glass washing and preparation areas break the most glass," he notes.
Although it isn't a perfect solution to the problem of breakage, many of the smaller specialty companies do offer glass repair. An expensive piece of glassware--an automatic buret, for example--can be repaired for about half the cost of a new one, says Bob Cheatley, president of Cal-Glass for Research Inc., a Costa Mesa, Calif.-based company that does repairs as part of its specialty glass business. "[Repaired items] don't look as good, but they're as functional as when they were new."
Despite the danger of breakage, glass has several advantages over plastic. Solvents, for example, can dissolve some plastics, explains Nicoll. Some plastics are gas-permeable, so materials that could oxidize or experience a pH change are usually stored in glass containers. In addition, glass is much more easily sterilized than most plastics, says Frank Nunziata, sales manager for Pequannock, N.J.'s Bel-Art Products; so where there's a sterility requirement, glass is used most frequently.
Plastic is sometimes chosen over glass because it is less expensive. For the glass industry, this has had negative consequences: As demand drops, prices have had to go up. But, unlike disposable plastics, glass can be reused. And although higher than the price of a comparable plastic item, the price of a reusable glass item is diminished with each use. "Convenience has a price," says Nicoll. "Per-use cost is typically higher for a disposable compared to a reusable product, even after figuring in washing and preparation costs."
Some companies have found a niche in the area of specialty glass. Scientists for whom a resident glassblower (see accompanying story) is not available can turn to specialty glass companies with their creative ideas for laboratory glassware. Cal-Glass's Cheatley recalls once being asked to make glass hearts--not pieces of jewelry, but true replicas of human hearts in which medical researchers could practice placing catheters.
Bellco also offers specialty glass items. Sometimes, says Nicoll, items that are specially designed for just one scientist turn out to have universal appeal and make their way into Bellco's catalog. "However," says Nicoll, "it seems that when specialty markets grow to a certain level for an item, somebody comes along and makes the item from plastic." Many of the more creative requests that Bellco has filled remain a secret--they arose from scientist customers in the pharmaceutical industry and are proprietary.
Cheatley is looking for new markets to beat the competition brought on by plastics and automation. The company recently introduced an all-glass photochemical treatment system called the EcoStill, which extracts silver from spent photochemicals. While the stills are targeted primarily for use in the photoprocessing industry, Cheatley expects them to prove useful in biological labs as a substitute for evaporators. Unlike standard evaporators, the EcoStill, an enclosed system, does not produce fumes, says Cheatley. And, he adds, the glass EcoStill is impervious to the chemicals that can damage standard stainless steel photochemical processors.
But sometimes glass just can't do the job. For example, "you can't squeeze glass," says Bel-Art's Nunziata, whose company's product line includes safety labeled squeeze bottles. Also, jugs and bottles for storage are frequently made of plastic because they are easier to handle.
In recent years, plastics have been developed with many of the properties for which glass is valued. For example, polymethylpentene is a very clear plastic with optical qualities nearly equal to glass. Polymethylpentene is also autoclavable, and is used for beakers, graduated cylinders, funnels, flasks, and many other items traditionally made of glass. Another clear plastic resistant to high temperatures is polycarbonate. Bel-Art markets a polycarbonate vacuum desiccator, used to remove moisture from a sample. A plastic desiccator has several advantages over the traditional glass apparatus, says George McClure, an engineer and senior corporate vice president of the company. Glass desiccators must be quite heavy to prevent implosion from atmospheric air pressure, a potentially dangerous accident. The polycarbonate can be taken down to a complete vacuum without danger of implosion, and won't crack or chip if it is dropped. The plastic desiccator is much less expensive than glass, McClure adds.
Plastic wasn't always intended to supplant glass, however. About 40 years ago, the first product of Rochester, N.Y.-based Nalge Co. was a plastic pipette jar. Nalge's founder, Emanuel Goldberg, was a manufacturer's representative selling pipettes, and many of his customers complained that when they dropped their glass pipettes into the stainless steel storage jar, the tips broke.
A chemist by training, Goldberg welded plastic bottoms to lengths of plastic pipe. "So, ironically, the first plastic product that Nalge made was designed to prevent glass pipettes from breaking," says Gordon Hamnett, national accounts manager for Nalge. "Subsequently, the company developed a lot of products that were designed because glass products were breaking. We developed a line of beakers, graduated cylinders, and volumetric flasks, modeled very much after the original glass benchware that was available commercially." Today, about 25 percent of Nalge's plastic items are disposable; the rest are made to be reusable.
The demand for plastic labware in the life science market has grown in the last decade, according to Hamnett. For uses in cell biology labs, some plastics have been designed to be more inert than glass, preventing cells from sticking to the surface. At the same time, plastic surfaces can be treated so that cells will stick and form a confluent layer more rapidly than they would on glass. "You can sort of pick and choose the features of the different types of plastic resins to satisfy different demands in the life science lab, where glass does not have the flexibility," says Hamnett.
And plastic technology is continuing to evolve, allowing manufacturers to make products for specific needs that offer advantages over glass and over other types of plastic. Nalge has a line of fluoropolymer (Teflon) beakers that can be used for handling hydrofluoric acid, which "basically eats glass," says Hamnett. The company is also experimenting with exposing a high-density polyethylene resin to fluorine gas to create a micro-thin layer, or "skin," of fluorine, resulting in a surface that has a chemical resistance similar to Teflon's, but is less costly. Nalge also has just introduced a disposable bottle made of the same material as plastic soda pop bottles--polyethylene terephthalate (PET). "PET is a resin that has gas barrier properties that are essential in cell biology, where media needs to be stored in a container that will minimize CO2 exchange," says Hamnett.
But even as plastic displaces glass, new lab procedures and a growing conservation ethic are cutting into the use of both materials. Automation and improved analytical instrumentation--often requiring very small samples--have reduced the demand for laboratory glassware, according to LaGrotte. "In the past, a scientist or a technician would do a lot of things by hand, using different types of lab glassware," he says. "Now there are various instruments that you just feed samples to, and they do all the analysis or mixing or whatever would have been done by hand."
While both glassware and plasticware companies now manufacture items, such as small sample vials, especially for automated use, Hamnett says that the decrease in the amount of glassware used for classic wet chemistry has been so great that the increase in automation-related items has not been enough to balance it out. Even though glassware and plasticware items are now available in both reusable and disposable forms, Stanley Pine, professor of chemistry at California State University, Los Angeles, advocates reusing even disposable items. "I'm trying to teach everybody that we don't live in a disposable world anymore," says Pine. "A lot of this plastic stuff that used to be thought of as disposable probably ought to be cleaned and reused."
"Cheap" used to mean "disposable," Pine says. While a reusable glass pipette might cost $10, a pipette designed to be disposable--made of thinner glass, with calibrations that are painted on rather than etched in--might sell for only $1. The manufacturer would argue that it's cheaper to throw away the disposable items than it is to handle them and wash them, he explains. "But many of us in the academic labs are finding a lot of the stuff that was made to be disposable is actually pretty good," Pine says. "It can be used, for example, in a lot of our undergraduate classes. Although it doesn't last for 20 years, it might last for five years, and it's probably economically advantageous."
Laurel Joyce is a freelance science writer based in Palo Alto,