McCrone Associates

For anyone who loves a mystery, McCrone Associates, part of the McCrone Group, has a plethora of stories to capture the imagination. Known for more than fifty years for their analytical services, the independent consulting lab has helped to solve crimes, identify foreign materials in products ranging from pills to plastics to electronics, and even dash a few dreams.

Two of its highest profile cases, analyzed by founder Walter C. McCrone and McCrone’s team of scientists, provided evidence that refuted the validity of the Shroud of Turin and the Vinland map. Neither the linen cloth, reputed to be the burial cloth of Jesus Christ, nor the map, a purported 15th century map of North America (Vinland) proving that the Vikings found their way to the Americas before Columbus, proved to be authentic.

Variety of Analytical Projects is the Fun Part of the Job

“Not all of our projects are like the Shroud or the Vinland Map,” says Kent Rhodes, Vice President & Director of Instrumental Analysis at McCrone Associates. “Many are much more routine, but the variety of the people and the projects is the fun part of the job. The great thing about being in the consulting business is that there is always a new challenge coming through the door. Our clients come from many varied disciplines and thus we continuously see a large variety of samples.”

For example, even a child’s sandbox sometimes requires the expertise of the scientists at McCrone, who raised the red flag on the asbestos found in play sand in the 1980s.

When automotive seatbelts failed without explanation, experts at McCrone used scanning electron microscopy to identify the root cause – tensile forces created during loading had broken the webbing fibers.

For another project, when windows in a new high-rise building were permanently streaked, McCrone identified the culprit; without a doubt, improperly applied cleaning liquids had done the irreparable damage.

Now in its 51st year, McCrone’s analytical lab has analyzed and identified samples from over 50,000 different projects, providing answers to a myriad of questions posed by researchers, industry, and forensic scientists. They have repeatedly answered the question, “What is it?”

Identifying Unknown Particles Led to the “Particle Atlas”
As the times change and technology advances, so do the samples sent to McCrone. Scientists at McCrone specialize in not only routine analyses but in identifying the most challenging, most indiscernible particles in metals, plastics, glass, drugs, food products, and even construction materials. In 1967 they literally wrote the book – The Particle Atlas, which was originally published as a single volume and then expanded into a six-volume edition in 1973. In 2004, a new online version, the McCrone Atlas of Microscopic Particles, was created and is continuously being expanded with new particle descriptions. This online version is available on a subscription basis.
A High Degree of Quality Control

“In recent years, our pharmaceutical business has increased significantly,” Kent observes. “With very stringent quality requirements, we have a lot of requests to respond to their manufacturing issues. Pharmaceutical companies require a high degree of quality control and documentation and we have devoted a lot of effort to it. Each month, we are audited by one or more of our clients and/or the FDA, and continually meet all regulatory requirements.”

Typical analytical procedures involving pharmaceutical products include particle analysis and particle size distributions, identification of contaminants, and drug polymorphism studies. All of these issues must be addressed before a product can be released to protect the consumer.

Handling Difficult Samples

“Our specialty is analysis of small samples and particulate material in samples,” says Kent. “In addition to pharmaceutical products, McCrone scientists examine a wide variety of materials; for example, pigment particles in paints and coatings, trace evidence for forensic cases, and thin films,” said Kent.

“We have a lot of very difficult samples that require isolating an individual, nanometer- or micrometer-size particle that might be the only example of its kind in a large amount of matrix material. We have just one shot at it – if it is lost, the project is over. Once we isolate it, we can perform analyses with three or four different instruments on that one particle.”

The particles to be analyzed are isolated and manipulated in an ISO Class 5 cleanroom, using specialized techniques developed at McCrone Associates. The sample is first observed with a light microscope to determine its size, shape, appearance, and physical properties, such as whether the particle is deformable, hard, soft, or magnetic. It is then isolated from the matrix and placed on a substrate for analysis with SEM (scanning electron microscopy) or EMA (electron microprobe) to determine its elemental chemistry and/or morphology. Depending on the nature of the particle, it may be further analyzed with IR or Raman spectroscopy, X-ray diffraction, SIMS, XPS, or TEM.

Careful Documentation

Projects are carefully monitored throughout the analysis process, sometimes in parallel with the client, as documentation is key. “We take photos of the boxes and sample containers when the project is opened, record the cleanroom techniques used for manipulating the particles, and fully document all of our analytical work. Some of our clients, particularly on forensic cases, need to observe every step of the process, so the pressure is on to perform this incredibly precise work while a group of attorneys is observing the entire process through the windows of the cleanroom.” Finally, the scientist must assemble all the data into a report that provides the client with the answers to, “What is it, where did that come from, and how can I get rid of it?”

McCrone Associates employs 45 scientists and technicians, each with an expertise in one or several disciplines and one or more analytical techniques. Every project is assigned a project leader to manage the project through resolution in the lab.

Corrosion and Glass Delamination

If the problem is corrosion, Kent Rhodes is one of three scientists that organizes a team to characterize and identify the corrosion product, analyze its phase, and determine the corrosion mechanism. They use analytical techniques such as light microscopy, SEM, TEM, and X-ray diffraction. For example, in identifying the particular compounds on a corroded steel pipe, knowing which iron oxide or iron hydroxide has formed provides clues to the cause of the corrosion and how it can be eliminated.

Analysis of glass delamination is another specialty of McCrone Associates. For example, the glass vials used for pharmaceutical products must withstand attack by many different chemicals and processes, including heat treatment and sterilization. Often, these chemicals can cause internal delamination on the vials, leading to small flakes of glass in the product, and discoloration of the vial. McCrone can isolate and identify the glass flakes, show where they were produced, and recommend steps to eliminate the delamination.

Airborne Particles

Recently, scientists at McCrone Associates collaborated with researchers at the University of Arizona to investigate airborne tungsten particles in Fallon, Nevada. The environment in Fallon has been intensely studied because of an unusual cluster of childhood leukemia cases in the last ten years. Previous work found elevated levels of tungsten in the air, but was challenged because tungsten minerals occur naturally in the desert around Fallon.

Using automated analysis software on a JEOL JXA-8200 electron microprobe, McCrone scientists were able to show that filters from Fallon contained tungsten particles characteristic of material from machine tools. Further analysis with a JEOL JEM-3010 TEM showed conclusively that the particles were tungsten carbide, a man-made material used mainly for machine tools or abrasives. It was also important to note that tungsten-containing mineral dust was not found on the filters from Fallon. Although tungsten has not been shown to cause leukemia, research is continuing on the health effects of exposure.

Fully Equipped Facility

In their 66,700 sq. ft. facility, McCrone Associates’ electron optics group has a 300 keV Transmission Electron Microscope, four conventional and field emission scanning electron microscopes, two electron microprobes, four mass spectrometers, two x-ray spectrometers, an XPS, and dozens of light microscopes.

“We have a lot of analytical equipment to maintain and keep operational,” Kent says. “With time being critical, if an instrument is not operational, it is not available to solve client problems. Therefore, it is essential that our analytical instruments be operational 100% of the time. In addition, for quality purposes, we are required to certify that our instruments operate correctly and being a small company we cannot maintain a full-time service staff. That is why we really appreciate JEOL and the outstanding service they provide. We have an excellent partnership and they work with us – that is why when you come to our lab you see seven different JEOL instruments. All of our equipment is under service contract, and the service managers in the local JEOL office do an excellent job working with us. We schedule preventive management around our client workload so that we can ensure time critical results.”

While McCrone’s services are often called upon for litigation, environmental, and industrial manufacturing purposes, the bulk of McCrone’s work lies in identifying miniscule particles in composites and materials ranging from soil to the latest medicine. They are called upon to find the needle in the haystack, or the particle in the pharmaceutical.

Multidimensional Organization

Founded in 1956 and located in Westmont, Illinois for the past twenty years, The McCrone Group, Inc., has become internationally recognized as a world leader in microscopy, microanalysis, materials characterization, and consulting. Under the leadership of Donald A. Brooks since 1975, The McCrone Group has become a multidimensional organization encompassing McCrone Associates - the analytical service and consulting firm; McCrone Microscopes & Accessories – the microscope and instrument sales group; the College of Microscopy – the microscopy learning center; – the online peer reviewed journal of microscopy; and the McCrone Atlas of Microscopic Particles – the online subscriber based atlas.

“Our charge today is to ensure that The McCrone Group continues to serve as the world’s Premier Microscopy Resource for our many clients throughout the world, as well as the scientific community,” said Brooks, President & CEO.

For more information, visit the McCrone Group website.

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