Nancy - log in and give a “2 minute warning before we begin”
Nancy: Thank you for choosing to attend our Webinar. Our presenters today are, Dan Olson, senior chemist at Element St. Paul with over 30 years expertise in Forensic and Investigative Chemistry, and me, Nancy Whaley. I began my career at Element St. Paul in 1988 as an analytical chemist and project manager, and joined the Investigative Team 8 years ago. Obviously, both Dan and I graduated from High School at the age of 5.
Nancy – Unbeknownst to clients, a chemical approach often can give great information in a cost efficient manner. Investigative Chemistry relates to problem solving. The problems can relate to metallic or non-metallic materials, solids, liquids or gasses, products or raw materials. We approach each project looking for chemical solutions – our failure and materials analysis groups look for physical or mechanical solutions.
Nancy: (animation) Because you need the right answers, in a timely fashion, and with cost efficiency, and we can help.
Over half of our project come from unsolicited sources. Clients initiate contact for many reasons – today, we will focus on some of the more common situations – We may receive a call because new product line has been introduced, a different colorant or dye has been added, an alternative chemical is desired for a process – in short – there has been a change in the manufacturing process or product.
We may receive a call because our client needs a test or analysis to comply with a law, a quality assurance procedure, or to import or export a product. Example of these types of tests are evaluation for a banned substance (such as lead in children’s products), compliance with European import laws for electronic equipment, or cleanliness testing for manufacturer parts.
Other clients will need evaluation of a product or part as proof that it meets criteria or a client will want to test for a specific chemical to prove it is not in the end product. Recent projects of this type included identification of O-ring materials before they could be used as well as analyzing a cloth for the presence of chemical to repel insects before and after a specified number of wash cycles.
Legal firms, defendants, or third parties will contact us for cases where legal defensibility of data is required. Cases in the past have included patent infringement, product claim disputes, and workman’s compensation.
The most common and often time sensitive potential project involve situation where an unexpected problem has arise: a product has failed during normal use – like the wires, failed before being placed in the field like the mp3 player screen, or a product is contaminated. In the far right picture, you can see within the oval circle a thin deposit on the surface of this printed circuit board.
When we are given the opportunity to help on any given project, we start by asking questions.
Nancy – We begin by garnering information directly from the client – in short – we are going to pick your brain Often the client has an idea what the problem might be and how to approach it, but a simple Q & A session can be very helpful in determining how to approach the problem. Other times, the client believes a cause and effect are related. Questioning can help clarify the project or expand the possibilities. After this discussion, we can formulate a project approach including suggestions for specific instruments or methods that will give the most information for satisfying the client’s needs.
The various instrumental approach we might suggest include…….
We also have access to colleagues with technical expertise in a variety of fields including metallurgical and polymer engineering, analytical chemistry, petroleum chemistry, materials chemistry as well as access to highly specialized instrumentation, NIST spectral libraries, and university resources.
Now that we’ve provided a glimpse into the world of Investigative Chemistry, let’s take a closer look at five specific cases….. In our first case today, we have an example of a product or process change. When a change in process occurs, we commonly ask the client….
A part was received for material verification – we had been analyzing this particular part number for this client for over 10 years. We use a technique called Fourier Transform Infrared Spectrometry (FTIR). FTIR gives us valuable information about the “fingerprint” for chemical composition of the material. Due to Element’s data archival system, we are able to compare data compiled for the same part number across time and lot number.
Preliminary analysis of the sample revealed enough difference from previous spectra to warrant further investigation…On the left we see the spectral “fingerprint” of the sample we received.
In order to confirm the unusual result, the sample was subjected to additional qualitative tests - if the chemical composition of the sample was unchanged, the sample would have produced a green flame when heated with copper wire, and the sample should have easily dispersed or dissolved in a specific solvent. When these results were not consistent with the sample’s chemistry, the client was contacted.
The client was offered a comparative analysis……..in short, we analyze a known good (reference or control) sample alongside a questionable or failed sample and compare the results.
An archived part known to have met the material specification was analyzed with the sample of questionable material. The left side spectrum is the questionable sample and the right side was the reference material. In direct analytical comparison, the sample on the left was a good spectral match to EPDM and the sample on the right was a chloroprene based material. We informed the client of the discrepancy.
Our client contacted his supplier. He found out that the supplier had changed vendors to an overseas source. The source had claimed equivalent material and material properties. The supplier went back to his previous vendor.
In our second case today, a client contacted because he was required to prove his product met a specification. In these cases, it is important to determine who is requiring the analysis. Often, analyses are required by government agencies such as the Consumer Products Safety Commission, the Environmental Protection Agency, or the European Union. Other times, the end user, such as Department of Defense subcontractors, and or nuclear related companies need to prove compliance. Sometimes, a manufacturer will ask for third party testing of their own products for compliance with internal quality requirements.
Almost always, in addition to the entity requiring the test, other details are needed. We will always ask if a method has been specified, if certain levels of compliance are needed, and/or if the laboratory doing the testing needs to be accredited. After the details have been reviewed and we assure the client we are able to assist, we initiate the project…..
In this case, a footwear company wanted to analyze each part of their products to ensure the shoes would meet criteria for sale in the United States with respect to lead. In order to comply with Consumer Products Safety Information Act of 2008, each part of the shoe that was unique (could contain lead) needed to be tested. With the client, we determined the number of individual parts in each piece of footwear, combined “like” parts into a representative sample (for example shoelaces of the same material and color), eyelits, and cloth. We ultimately tested 35 samples on 9 different shoes.
The parts were digested in the appropriate acids. Because the samples varied in materials, slightly different preparation processes were used for different sample types. The resulting samples were analyzed by inductively coupled plasma for lead content.
The results revealed that a specific colored part (sole) of only certain footwear exceeded the lead limit. The client consulted with his supplier, together they changed production material and formulation. Subsequent parts were submitted for analysis until the lead criteria were satisfied.
The product is now compliant with CPSIA of 2008. The footwear is readily available in the United States.
Sometimes, a client approaches us for support already knowing what chemical or material is targeted. In this specific case, a medical device manufacturer needed us to look for a specific chemical – acridine in several different batches of resin used in their manufacturing process. Further discussion with the client revealed that acridine had been detected in a quality control test of the end-use product, and the source needed to be determined.
The client did not have a specific method, but indicated that gas chromatography in conjunction with mass spectrometry had been discussed within the company.
Further research on the compound’s physical and chemical characteristics revealed that Selective Ion Monitoring (SIM) gc/ms was a feasible approach because we were only interested in a single compound. Sample preparation techniques were required that would leach the acridine into a liquid without dissolving the resin or interfering with the analysis. After the project approach was determined and the correct solvent chosen, the project was initiated.
Our first step was to verify that the technique proposed was applicable. Standards containing the component at 2 different concentrations were analyzed and evaluated for retention time and mass spectral information. Once the instrumental approach was confirmed, the samples were extracted and analyzed.
The chromatographic data on the left (at the selected ion of 179 – the molecular weight of acridine) are typical of all but one of the samples in the 10 total resins submitted for analysis. The data on the right side generated for sample C.
At first glance, it might seem that sample C is leaching a large amount of acridine. However, if we look closer at the data, the relative peak heights show that, if present, the acridine was extracted from the resin at less than 1 part-per-million.
The client was able to screen the resins and isolate a potential source of the undesired chemical. The project approach we developed was much faster and more cost effective than alternate methodologies.
A potential client will contact Element St. Paul looking for legally defensible data. These projects do not require us to approach the analysis differently from a technical or quality standpoint, but the work is documented in a way that allows for easy recall, reproducibility of data, and traceability in the eventuality that the case might go to court at a later date. For this project a three-party lawsuit, a grocery store, a contract cleaning company and a carpet manufacturer were involved because a carpet product was fading less than 12 months after installation. A warranty claim to replace the carpet was rejected by the manufacturer based on test performed on a new, un-used section of carpet. The manufacturers representative tested the new carpet for color-fastness under varying conditions.
To verify the information provided the client about wear pattern and to ensure proper sample collection, an on-site inspection, including photographic documentation was performed. At the site – the carpet manufacturer and type was identified by the purchaser. Additional observations were made as follows: 1. The carpet exhibited a checkerboard pattern with alternate squares having blue-grayish and light grayish backgrounds. Reds, purples and teal colored fibers were present in both areas. 2. The carpet exhibited a similar pattern of fading throughout the store with the highly trafficked areas exhibiting the greatest loss of color. However, in these areas, the reds, purples and teal colored fibers faded to off-white. Alternating bands of more faded and less faded colors were visible in the wider areas of the carpet, particularly along the front end of the aisles. The bands were relatively straight, parallel and constant in width. At this point, further discussion revealed that the carpet manufacturer claimed that the carpet warranty had been invalidated by improper cleaning and treatment of the carpet.
Based on the on-site observations and additional information provided by the client, four samples were collected and submitted for analysis: One section of faded carpet One reference section of carpet (not faded but installed with the faded sample) one gallon of pre-spray carpet treatment one gallon of liquid carpet cleaner
The exact type of carpet was researched. The manufacturer’s information sheet listed the carpet as nylon with 14 different colors. Both solution-dyed and yarn-dyed methods were used to produce the colors. This was an important fact because yarn-dyed colors are limited to the surface of the fiber while solution dyed colors are inherent to the entire fiber.
The faded and reference samples were then visually inspected and photographed in the laboratory. The left photograph is the reference (non-faded) sample and the right is the faded sample. The visual inspection revealed that the carpet had faded throughout the entire sample, but certain colors seemed more affected than others.
Many dyes are UV active – this means they fluoresce under ultra violet light. Therefore, the samples were subject to a UV light with revealing results. The reference section of carpet had patterned fluorescence while it was obvious that the faded carpet had undergone marked change.
The faded and reference samples were then examined microscopically in several areas. Throughout the microscopic evaluation, it was noted that the purple, red, and teal colored fabrics displayed the most susceptibility to fading. In many areas, these threads had faded to off-white. There were no off-white areas in the non-faded reference sample.
Microscopic examination of the samples revealed small gel-like particulate. This particulate matter was scraped and collected for further chemical analysis
The next phase of the project involved chemical analysis to directly address the manufacturer’s claim that improper use of acidic cleaning materials caused the fading. Our approach included cutting several, different colored tufts of fibers from three different areas within the faded and non-faded areas. The six samples of tufts were placed in glass vials containing deionized (DI) water, sonicated, and tested for pH using indicator strips.
The cleaning solutions were diluted according to manufacturer’s instructions. The pH’s of the resulting solutions were measured. The results, shown here, indicate that neither the faded or non-faded threads contained acidic residue. Therefore, the manufacturer’s claim that the carpet had been improperly exposed to acidic conditions was not substantiated.
The gel-like particulate matter was analyzed by FTIR for determination of chemical composition. The particulate matter was silicone-based. Silicone based materials can be used as sealants. There was no indication that acidic residue was present in the gel.
Based on the on-site inspection, results of research, visual, and microscopic evaluation and chemical analysis, our conclusion was that the manufacturer’s rejection of claim based on improper exposure to acidic conditions was not supported. Specifically, we noted that: 1. The yarn dyed method may have been used to produce the reds, purples and teal colors. Because yarn dying creates less color fast fibers compared to solution dying, those fibers would, most likely, be more susceptible to fade/wear. 2. If the carpet had been improperly exposed to acid cleaning materials, the carpet fibers would have been acidic when extracted in DI water and pH tested. Instead, the extracts were neutral or slightly alkaline. We concluded that the faded sections of the carpet resulted from loss of the yarn dyed colors due to wear. The claim was resubmitted with the reported findings.
A high percentage of our calls and repeat business can be categorized as situations where a product or process has failed. Because these circumstances have cost and/or public relations implications, these projects are usually high priority for our clients to resolve. In this case, the client originally contacted us describing the problem as a haze that could not be cleaned from one of their products. The product had been installed in an exclusive residence.
Animation: The client submitted a representative window for analysis. The following observations were made upon preliminary evaluation: 1. The window sash measured 52&quot; x 83” – it was large and cumbersome to work with indicating the importance of the project to the client. 2. The window frame and muntins were constructed from unidentified hardwood(s). 3. The muntins divided the window into 15 individual lites but the sash contained only two glass large panes, interior and exterior. 4. The haze was evident when the window was held at angle to the light. 5. Attempts to clean the haze with various solvents were not successful. We concluded that the haze was on the interior surface of both window panes.
After the initial evaluation confirmed the client’s general observations of the problem, the client was asked specific questions about the materials comprising the sash. The client indicated that: 1. The perimeter of the double-pane glass was sealed with a thermoplastic elastomeric sealant. The glass/wood interfaces along the pin-nailed muntins were sealed with rubber rolled strips. 3. The glass faces were coated with a low-E Pyrolytic. 4. The gap between the two glass panes was air-filled not argon filled.
Based on all the information, an analytical approach was designed to: Expose the interior surfaces of the glass IF possible, isolate the haze for instrumental analysis Analyze the sample by Energy Dispersive Spectroscopy (a technique which identifies the elements that are present) and FTIR to evaluate chemical composition
Broken shards were examined and photographed. A faint, non-uniform purplish haze is visible on the top surface of this fragment which corresponded to the interior surface of the glass.
EDS analysis was performed on three areas. The EDS scan above depicts the chemistry of the area with no e-coating. This data reveals that the glass is soda-lime type.
EDS data were also collected on a coated reference (no haze) area on the glass shard (left) and hazy area (right). These data indicate that the low e-coating on the interior surfaces was tin-based. The large amount of silicon in the EDS scan in the figure on the left indicated the electron beam from the instrument penetrated through the tin coating and into the underlying glass.
Using this information and the Kanaya-Okayama Depth Penetration formula, the coating on the interior surface of the glass was no more than 2µm thick. Therefore, the haze-producing films were too thin to exhibit visible fluorescence and were too thin to detect by microscopic-FTIR. The slide provides a relative idea of how thin the e-coating was.
Because the hazy film was so thin, x-ray photoelectron spectroscopy (XPS) was proposed. The depth of analysis for XPS is 50-100Å which equals one-half to one micron (µm). XPS provides information on the elements present and their relative atomic concentrations.
An area free of haze could not be located for XPS analysis, so two areas of differing haze appearances were analyzed. The elemental compositions between the more hazy and less hazy areas varied most significantly in the carbon, oxygen and tin levels. Based on the values in the table, the more-hazy area consisted mainly of tin oxide, probably SnO2 or hydrated SnO2, both of which are white powders.
Based on our examination/analyses, the faint haze visible in the window sash was produced by a very thin, non-uniform film of contaminants on the interior surfaces of both glass panes. The main component in the haze-producing film was tin oxide (SnO2) and/or hydrated tin oxide (SnO2•xH2O), a.k.a. metastannic acid. Both compounds are white powders which could reflect and/or diffract light when present as very thin films.
We concluded that the haze was probably due to corrosion products of tin. In order for corrosion to occur, sources of oxygen and moisture are needed. A likely source of the oxygen would be the air used to fill the insulated space between the two glass panes since air is 21% oxygen. There are several potential moisture sources: The air used to fill the insulated space between the glass panes could have contained a trace amount of moisture. Another potential source of the moisture could be a sealant or adhesive but only if this material outgases moisture during the curing process. Free moisture may have been present within the insulated space for a relatively short period of time before combining with the tin oxide forming the hydrates.
Nancy: This concludes ou look today at asking the right questions and reviewing projects where further investigation was needed. To summarize what we hoped we highlighted today (animation) 1. The amount of information provided can be crucial to the direction, time and the cost of the project. Additional questions (and therefore, lines of communication) are important at the beginning, middle and end o the project The project approach and methods may change as the project progresses. But.. MOST importantly, working together, using an investigative chemistry approach, we (you and Element St. Paul) can successfully meet any challenge.
Nancy, at this time, Dan and I would be happy to answer any questions you might have. If you have questions at any time, please don’t hesitate to contact either our sales team or Dan or I. Again, thank you. Leave the next slide up for the Question and Answer period.
Leave this slide up – prepare a dummy question: Is there a good way to submit samples to the laboratory? General cost of analyses?