Sponsored by Encana Corporation
Professor Janusz Pawliszyn
Solid-Phase Microextraction (SPME) for Solvent-Free and Efficient Sampling and Analysis of Solid, Liquid, or Gaseous Sample
- Professor Pawliszyn, PhD, is the inventor of solid-phase microextraction
- Chemistry Professor at the University of Waterloo, Ontario, Janusz Pawliszyn holds the National Sciences and Engineering Research Council (NSERC) Industrial Research Chair, and Canada Research Chair in New Analytical Methods and Technologies (See http://www.nserc.gc.ca/partners/profile_detail_e.asp?pid=305 and http://www.chairs.gc.ca/web/chairholders/viewprofile_e.asp?id=1044&UniversityID=&SubjectID=&DisciplineID=&Researcher=&Date_Announce=&Keyword=pawliszyn)
- Solid-phase microextraction (SPME) is an environmentally friendly, convenient and efficient technology for collecting and extracting samples for chemical analysis
- An SPME device consists of a small syringe and needle that house a miniature "dipstick," typically a coated metal wire the width of a hair
- SPME devices are tailor-made to allow for selective extraction of specific chemicals from a sample, such as fire-starters in arson debris, toxins in drinking water, pesticides in fish, flavour components in wine or coffee, medications in blood or the chemicals that give a flower its fragrance
- Before the commercial development of SPME, chemical testing was typically tedious, inefficient and indiscriminate, and required the use of hazardous organic solvents for extraction
- Unlike older methods, SPME collects samples and extracts chemicals of interest on site so that large volumes of sample material do not have to be transported back to the lab
- Professor Pawliszyn invented and continues to develop SPME technology in his research lab at the University of Waterloo, Ontario, Canada
- US based company Sigma-Aldrich/Supelco and its partners and customers have supported commercial development of various SPME systems
- SPME products are sold worldwide and used by major environmental testing agencies, research laboratories and forensic laboratories in the Americas, Asia, Australia and Europe, including the US Army and the US Navy, the US National Center for Environmental Health, and the Canada Centre for Inland Waters
- Professor Pawliszyn's experiments using optical fibres for SPME in the late 1980's led to a major patent (filed in 1990), then development of the commercial manual SPME system (1990-95) and commercial automatic SPME system (1995-2000); additional SPME devices and calibration procedures for on-site or in vivo sampling have followed
The basic SPME device is a small and sturdy syringe and needle that contain a miniature fibre "dipstick." To collect a sample, the tester depresses the syringe plunger to project the centimetre-long fibre. The fibre, either fused silica or a metal wire the width of a hair, picks up the sample in minutes before being drawn back into the needle for safekeeping.
Alternatively, a coated capillary or flat membrane can be used in place of a fibre in order to draw up the sample. Back in the lab, chemicals of interest may be directly injected into analytical device, either manually or automatically. Researchers have also devised robotic arms to prepare multiple samples at once.
"It's a good tool in the analytical tool box," admits inventor, Professor Janusz Pawliszyn.
Before commercial development of SPME in the mid-1990s, chemical testing was typically very tedious. Like an indiscriminate fishing net, older sampling methods picked up a range of chemicals, not only those of interest. Relatively large volumes of water or other environmental samples had to be transported from field to lab for extraction and analysis. Plastic collection cartridges, along with the hazardous organic solvents used to extract chemicals of interest, could contaminate samples and interfere with results.
SPME transformed chemical testing by simplifying the extraction step and integrating it with sampling. The state-of-the-art technology is convenient, portable, effective and solvent-free.
Picking up the Scent of Success
Professor Pawliszyn is recognized not only for his innovation in developing the theory behind SPME, but also for putting theory into practice by building various SPME devices. Today there are over 60 products in the Supelco SPME product line. Since its commercial launch in 1993, the technology has generated over $20 million (USD) for Sigma-Aldrich/Supelco and $1 million in royalty revenues for the University of Waterloo.
Fragrance components, pesticide residues and chemical weapons are just a few of the wide range of chemicals suited for SPME. For example, investigators used SPME to test for toxins in the air at Ground Zero at the World Trade Center after 9-11.
"Actually, there are no limitations to (its) application," says Professor Pawliszyn. Simply by changing the coating on the fibre, an SPME device can be tailor-made to selectively pick up almost any chemical.
When a perfume-maker called from the Caribbean to say "thank you, for making me rich!" Professor Pawliszyn learned firsthand of his innovation's impact on the fragrance industry. Now scientists had a way of sampling the air around a flower in order to find out exactly which chemicals made up the scent.
"One is almost tempted to say that we can now see what we smell," says Swiss fragrance and flavour company Firmenich. The company uses SPME to prepare samples for analysis with gas chromatography and mass spectroscopy. Because of the precise results they obtain, they are able to create true-to-nature replicas of the scents of flowers and fruits.
An evolving application of SPME is to take samples from living organisms. Compared to drawing vials of blood, for example, SPME is much less invasive. In a current project, Professor Pawliszyn and collaborators are using his technology to search for pesticide residues and antibiotics in fish. The fish are caught, pricked with an SPME device and then released. In the past, scientists would have had to kill the fish and grind up the organs for chemical analysis.
Professor Pawliszyn is also working with medical researchers using SPME to monitor chemical changes in the body. Our blood, sweat, tears and breath contain metabolites-chemical clues about the body's response to age or stressors such as disease.
As the technology becomes more sophisticated, he notes, more complex investigations are being done. A major goal of his Canada Research Chair is to take sample collection and extraction one step further, and perform on-site analysis.
Eco-Friendly Chemical Solutions
For Professor Pawliszyn, the original push to develop his innovation came from knowing how much it could benefit the environment. The large volumes of organic solvents typically used for chemical extraction are a danger to work with and an environmental hazard. With SPME, however, no organic solvents are needed.
He is hopeful that as SPME becomes even more widely adopted, the technology will significantly alleviate the burden of chemical waste on the environment.
Not only is SPME an eco-friendly extraction method, it is speedy and has expanded the possibilities for environmental testing. With older methods, it takes about an hour to extract chemicals from water samples such as sewage effluent. With SPME, extraction takes two minutes, and so labs can run hundreds of times more tests per year than before.
Thinking Outside the Cartridge
The idea for SPME grew out of experimentation with fibre optics. At first, Professor Pawliszyn was using laser pulses to rapidly dissolve chemicals from optical fibres as a way of introducing chemicals to analytical devices. It was after joining the University of Waterloo in 1988 that he realised that coated fibres would also make excellent extraction tools.
Graduate students in the newly established Pawliszyn lab began "playing" with coated optical fibres. But the fibres kept breaking. "Eventually," says Professor Pawliszyn, "one day, early in the morning, I woke up and said 'oh yes!'" Why not protect the fibre by putting it in a syringe needle?
The invention, says Professor Pawliszyn, came out of using available technologies in "new geometries," and in thinking about how to quantify samples in a new, more convenient way.
With the support of NSERC, and later, industrial partners Varian, Inc. and Sigma-Aldrich/Supelco in the United States, Professor Pawliszyn commercialized the SPME device, making it available to analysts in areas as diverse as environmental science, medicine, food science and forensics.
Initially, says Professor Pawliszyn, many researchers were puzzled as to how a tiny fibre could possibly collect enough material for meaningful analysis. But unlike older methods, SPME collects a concentrated amount of chemicals, all of which can be injected into an analytical device.
Sceptics also questioned how they could use SPME for quantitative extraction, for example, to find out how much toxin a water sample contained. The answer is simple, says Professor Pawliszyn, but not obvious. The surface area of the fibre and thickness of the coating gives the analyst a way of calculating volume. Combined with knowledge of how well the toxin sticks to the fibre, it is possible to calculate its concentration.
"When (a technology is) new, it's sometimes surprising what it can do," the innovator says. But as he has told his 100-some graduate students over the years, "life is a laboratory. Experiment!"
The Ernest C. Manning Awards Foundation
This year the Foundation will award $165,000 in prize money. Four awards, totalling $145,000, will go to leading Canadian innovators. Another $20,000 will go to Young Canadians chosen at the 2008 Canada-Wide Science Fair.
The Foundation was established in 1980 in the name of prominent Alberta statesman, Ernest C. Manning, to promote and support Canadian innovators. Since 1982, the Foundation has presented over $3.9 million in prize money through its annual awards program.
This is the fourth time in ten years that a Waterloo nominee will receive one of the Foundation's innovation prizes. Professor Pawliszyn joins Manning Award winners Dr. En-hui Yang (2007), Mike Lazaridis and Gary Mousseau (2002), and Roman Baldur (1999).