Extractor Makes Commonly Used Chemistry Laboratory Device Obsolete
tool offers increased efficiency and versatility
1999 R&D 100 Award Winner
Gregar extractor, invented by Argonne's Joe Gregar and Ken
Anderson, represents a major advance in solvent-based chemical
extraction from solid samples. The new design, available in two
different configurations and several sizes, eliminates problems
associated with conventional Soxhlet technology and can shorten
extraction times. Argonne's Gregar extractor features a revolutionary
new mode of continuous extraction, and it is uniquely adjustable
to serve multiple extraction applications.The extractor is available
The most useful inventions often spring from solutions to small
problems encountered during the pursuit of larger ones. A case
in point is a new device that promises to render obsolete a standard
device used in virtually every high school, industrial and university
chemistry laboratory in the world.
The new device performs one of the chemistry lab's most basic
day-to-day activities: it extracts chemicals from a solid and places
them in a liquid, the form needed for most chemical analysis. And
it does so more efficiently, more reliably, and usually faster
than the Soxhlet extractor, which has been the chemist's workhorse
for this task since the middle of the 19th century. The new device,
called the Gregar extractor, also eliminates many of the operational
problems associated with the Soxhlet extractor and performs chemical
extractions that a Soxhlet extractor simply can't do.
The Gregar extractor was invented by scientific glass
blower Joe Gregar and chemist Ken Anderson, both of Argonne's
"The Gregar extractor is elegantly simple," Anderson said, "essentially
just allowing a liquid to find its own level. But it's a useful
tool for chemists, something that's going to make extractions a
Already, the Gregar extractor has advanced Anderson's research
by making it possible to complete extractions he could not have
done before. In fact, the driving force behind the Gregar extractor's
invention was a problem Anderson encountered while using the Soxhlet
Anderson studies the natural processes that convert decayed plant
life into coal. A key step in his research involves the analysis
of amber, naturally formed fossil resins that provide a chemical
snapshot of the plant decay process. Anderson used a Soxhlet extractor
to remove compounds from amber for analysis. But amber swells when
exposed to solvents, and the swelling creates problems for Soxhlet
The Soxhlet extractor carries out a series of cycles, with solvent
vapor rising into the sample chamber, condensing, dripping over
the sample and collecting at the bottom. When the liquid rises
to a certain level, it automatically siphons out, and the process
But the cyclical process can create problems, particularly with
samples, such as amber, that tend to swell and break up when soaked
To overcome these problems, Anderson went to his colleague Joe
Gregar, a fourth-generation, master scientific glassblower.
Over the ensuing eight months, they designed and hand-built a
series of components and prototypes, each one coming a bit closer
to solving Anderson's problems. The result is the "Gregar extractor" --
a major advance in chemical extraction technology.
The Gregar extractor improves on the conventional extractor in
a number of ways. It uses a porous glass "frit" instead of filter
paper and replaces the cyclic siphoning action with a continuous
solvent flow. In addition, redesigned glass arms and two new valves
allow the Gregar extractor to perform extractions that are impossible
with a Soxhlet extractor.
It can also make extractions faster. "We can't say the Gregar
extractor is always faster than the conventional extractor," Anderson
said, "because extraction time depends on the specific sample.
But we can say it's never slower."
Two new valves make the Gregar extractor more versatile than any
other extractor on the market.
"By opening and closing the valves appropriately, you can extract
liquids from liquids," Anderson said, "something you could never
do with a Soxhlet extractor. One setting lets you perform extractions
from liquids that are denser than the solvent, and another lets
you work with liquids that are less dense. There's no other extractor
out there that can do all this."
Nor have Anderson and Gregar stopped with just one version. So
far, the co-inventors have produced two different configurations
of their basic extractor, both fully developed and demonstrated.
The potential market for the new apparatus is huge: Most chemistry
labs around the world have several Soxhlet extractors on hand.
Argonne has licensed the new technology to Kontes Glass Co. of
Vineland, NJ. Development of the Gregar extractor was funded by
DOE's Office of Energy Research, Basic Energy Sciences, Chemical
Just how significant is this invention? Anderson and Gregar acknowledge
that their creation is simply a tool -- but a highly useful one
It has no disk drives or serial ports, no microchips or gauges
or wires. It doesn't even have an "On" switch. Most of the materials
and techniques required to build it were developed before Anderson
and Gregar were born. Yet this simple, streamlined device seems
destined to make every chemist's job easier and to put Gregar's
name in every chemistry laboratory in the world.
Gregar Extractor Advantages
- Faster extraction than standard soxhelets (up to 50% depending
upon the compound)
- Continuous extraction
- No more"chugging" flow after siphoning occurs
- No more solvent hangup in the siphon tube
- The Gregar Extractor is specifically designed for difficult
extractors such as when the sample expands/swells or for"sticky" compounds,
such as coal, plastics, resins, etc. It works just as well for
- 3-way valve permits ease of use and flexibility
- More efficient solvent extraction
- No more solvent bypassing the sample due to packing or
- A variety of sizes and configurations are available
- Horizontal, vertical, or mini-size
- Quick release valve for draining
- No"dead" spots for solvent or air bubbles
- "Easy fill" side leg attachment
- Can be fitted with a cold leg condenser
D413,678, Solid Liquid Extracto.
Argonne has licensed the Gregar extractor technology to industrial
companies, including Kontes Glass Company (Vineland, New Jersey)
and Chemglass (Vineland, New Jersey). Argonne is seeking
The Gregar Extractor is the winner of a 1999 R&D 100 Award. The
development of the extractor was funded by the Department of Energy,
Office of Science, Basic Energy Sciences, Chemical Sciences Division.