Headspace gas chromatography (GC) is a way of separating volatile material from a liquid or solid prior to analysis. This sounds straightforward enough, but there are a number of process control issues where analyst error could affect the results, thereby providing the defense attorney ammunition for a wounding cross examination. One critical area facing scrutiny is the sample collection and preparation itself.

BAC Analysis Begins Long Before Headspace Analysis

Determining the ethanol levels in BAC analysis by headspace gas chromatography begins long before the instrument analyzes the sample. The analyst needs to ensure that the identifying information on the sample corresponds to its packaging. He or she also should look for conditions that could affect the reliability of the analysis, such as leaks, blood volume, clotting and signs of fermentation.

Clotting will lead to a false high result because the standards that the unknown are compared against are designed to test for whole blood and not the serum resulting from clotting. Fermentation can lead to a false high result because ethanol can actually be created in the sample after it is withdrawn from the defendant.

Unequal Temperature of Samples Can Cause Problems

The specimens and standards must be allowed to reach room temperature. Unequal temperature may lead to unequal sampling volumes. If the volume of the defendant’s blood sample is different from the known ethanol standards, then the results will be invalid. All the vials must contain the same volume of liquid for the test to work properly. In addition, the specimens should be rocked or gently inverted to assure the sample is homogenous.

If the vials are vigorously shaken, this can cause bubbles in the sample which will increase the

volume of the sample and lead to invalid results. The analyst must then properly prepare the vials that go into the auto-sampler. The analyst introduces the blood and the external standards into the separate 20 milliliter (ml) headspace vials, using a properly calibrated pipette.

Pipetting Fraught with Potential for Error

Also using a pipette, he or she introduces a precise volume of internal standard into every vial, with the exception of the water blank vials. The manual pipetting of these solutions in such small volumes is inherently fraught with the potential for error. The analyst must exercise extreme care in order to ensure consistent samplings of both the specimen and the internal standard. Consistency is critical to precision and reproducibility.

That’s just the first step in a long chain of evidence process from taking of a BAC sample at the time of arrest to the time of prosecution. A lot can happen in the lab and during subsequent steps, such as the pipetting technique used, loading of the vials into the machine, selection of parameters for the test and final interpretation of the results that can point to a tainted sample.

BAC Test Errors Offers DUI Defense

A good defense attorney can create a viable road map of BAC test errors and lead a jury to believe that the blood sample was contaminated and therefore prejudicial to his client. A good analyst will be able to document the quality process controls in place and the specifics of how each vial was prepared. He must also be trained to be aware that sample preparations may affect a test result. It is the lack of this awareness that a skillful criminal defense attorney can expose on cross-examination.

Subscribe to the Innovatech Labs Resource center to learn more about material analysis techniques like headspace analysis, ion chromatography, and fourier transform infrared spectroscopy.

Headspace Analysis and Blood Alcohol Test Errors was posted at Materials Analysis Provider Innovatech Labs Newsroom – Innovatech Labs. | http://www.innovatechlabs.com/newsroom

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It’s an excellent technique for analyzing contamination, stains and passivation layers to maintain quality control in markets such as thin film technology, optic coatings, superconductors, MEMS and more.

3-Step AES Analytical Method

1) Ionization of a core electron – The atom is ionized by removing one core electron. The ionization of the core electron is produced by a primary electron beam with an energy of 3 keV or more.

2) Upper level electron falls into the lower level vacancy and thereby releasing a quantum of energy. (Quantum is the smallest unit of energy.)

3) Energy that is released from the second electron  excites an outer shell electron resulting in the emission of a third electron known as an Auger electron.

Once the Auger electron leaves the atom, its energy is measured using the energy spectrometer.  The measured energy is used to identify the atom (i.e. element) that emitted the electron and thus gives information on the surface chemistry of the sample. The  energy analyzer is usually a cylindrical mirror analyzer. The detector contains an electron multiplier which consists of di-nodes which are connected to a resistor. The second electrons are produced in this step. Data is then processed by mapping the spatial distribution of the surface constituents and obtaining an in-depth profile of these constituents into the bulk of the material.

Advantages & Disadvantages of Auger Electron Spectroscopy

Auger electron spectroscopy is becoming simpler to use. It registers with high sensitivity when chemical analyzers are run and its output rates are high during data processing. The principle advantage ofAESis its high spatial resolution (ca. 1 micron or less).

One disadvantage toAESis that surface damage may occur when electron beams are processed. And, more precision requires more work to retrieve precise data.  Finally, insulators ofAESare sometimes complicated to study when surfaces are being charged.

How Stuff Works: Auger Electron Spectroscopy Testing was posted at Materials Analysis Provider Innovatech Labs Newsroom – Innovatech Labs. | http://www.innovatechlabs.com/newsroom

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Chemical spills, emissions monitoring, contaminated land, toxic smoke, and testing of cargo containers are just a few of the applications where on-site FTIR analysis is vital to the health and safety of industrial workers and first responders.

Toxic Industrial Chemicals (TICs), Volatile Organic Compounds (VOCs) and Chemical Warfare Agents (CWAs) are all part of our “advanced” society. The availability of a portable FTIR gas analyzer that mimics precisely the on-line version means that testers have an effective backup system, so that they don’t have to worry about loss of data or can provide a rapid response in a health, safety or environmental emergency.

Improving Air Quality On Site

It’s possible to measure emissions and make adjustments at a power station, for example, that meet or exceed compliance regulations thus improving occupational safety and environmental health. Having a portable backup system identical to the fixed installation means the facility manager could swap out monitoring systems or move the system to another station, if necessary.

By using a portable FTIR gas analyzer, the power station benefits from higher levels of accuracy and lower levels of maintenance as a result of continuous calibration. In addition, the cost of new monitoring equipment is small when compared to the cost of new abatement equipment that would reduce particulates, acid and other gases. The convenience of portability is an added bonus.

Detecting Hazardous Gases Quickly

Consider that shipping companies fumigate cargo containers, wooden packing materials and foodstuffs to control the spread of pests and micro-organisms. Fumigant gases are toxic so containers are monitored on arrival at each new port or destination for health and safety purposes.

In addition, products shipped in containers can release VOCs from solvents and glues used in the manufacturing process, and their concentration may accumulate in the confined space of a container.

While FTIR testing offers major advantages over portable monitoring technologies because of its specificity and lower susceptibility to interference gases, from a safety perspective, it’s extremely important to be able to detect hazardous gases as quickly as possible.

Looking at the value of FTIR from a security angle, the ability to measure TICs and CWAs is a considerable added benefit. By avoiding the cost of laboratory analysis, operational costs are reduced considerably, as well.

FTIR That Fits in a Backpack

A portable FTIR gas analyzer can detect, identify and measure up to 25 compounds. The collection of a complete sample spectrum means that over 250 compounds can be analyzed simultaneously and within seconds of startup. The portable analyzer provides laboratory grade analysis in a field instrument that our grandfathers could only dream about. Today, it’s a reality.

The Benefits of Portable FTIR Gas Analyzers was posted at Materials Analysis Provider Innovatech Labs Newsroom – Innovatech Labs. | http://www.innovatechlabs.com/newsroom

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Reasons for Compromised Data

You want to be certain the analytical lab you choose follows the EPA Test Method 320 and provides complete and thorough technical documentation. Common deficiencies that can compromise the validity of your source test may include:

• Misidentified spectral interferants
• Missing or incomplete EPA Method 301 validations
• Failure to apply systematic bias factors from 301 validations
• Failure to prove both transport and analysis of soluble and reactive compounds
• Lack of documented spectral backgrounds
• Improper or missing documentation of detector linearity, system noise and leak checks
• Lack of documentation of tracer gases or mass flow controllers used for dynamic spiking

Litigation Support

If you represent a business which has been cited for emissions violations, then you’re going to need to defend those results in court. When you combine the law with science, however, you’ve just added a layer of complexity uncommon in most courtrooms.

You want analysts experienced with numerous source types, who can add meaning to the emissions measurements gathered.

Your legal team should include a chemist or chemists with experience in Stack Testing, FTIR Spectroscopy, CEMS Services, Industrial Hygiene Monitoring, Air Dispersion Modeling and/or Mercury Monitoring. More importantly, you need that person to be able to explain complex chemical concepts in terms that lay persons can understand.

Your vetted expert should be able to assess the strengths and weaknesses of evidence or the prosecution’s experts’ testimony. You want an expert opinion on the validity of the work performed. When lawyers defend microscopic measurements, you want a strong opinion on the validity of current work, whether the most appropriate method was used, potential sources of error and any other factors that might affect the suitability of data for use as evidence.

In other words, you want to be sure your expert testifies with confidence and precision, and that he’s more qualified than the other guy.

There’s no substitute for experience when providing FTIR-based emissions tests.

FTIR Emissions Testing: Common Pitfalls was posted at Materials Analysis Provider Innovatech Labs Newsroom – Innovatech Labs. | http://www.innovatechlabs.com/newsroom

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This science fiction scenario is being played out on Titan now, as you do your job here on Earth, minus the human element. With its thick atmosphere and organic-rich chemistry, Titan resembles a frozen version of Earth, several billion years ago, before life began pumping oxygen into our atmosphere.

Cassini Journeys to Saturn

On its journey to Saturn, the Cassini spacecraft carried the European-built Huygens probe. OnJanuary 14, 2005, Huygens achieved humankind’s first landing on a body in the Outer Solar System when it parachuted through Titan’s murky skies.

Huygens took measurements of atmospheric composition and wind speeds during its descent, along with an incredible series of images showing telltale patterns of erosion by flowing liquid. The probe came to rest on what appeared to be a floodplain, surrounded by rounded cobbles of water ice.

Among the many instruments aboard the Huygens probe is the GC/MS, which was developed by NASA Goddard Space Flight Center’s Planetary Environments Laboratory. The GC/MS is being used to study the chemical composition, origin and evolution of Titan’s atmosphere.

Mass Spectrometers in Space

GC/MS has been used on space missions since the Mars Viking missions in the mid-seventies. Mass spectrometers are now widely used in space missions to measure the composition of plasmas.

Set to launch in 2013, a new Mars mission, dubbed MAVEN (The Mars Atmosphere and Volatile Evolution Mission), will utilize a Neutral Gas and Ion Mass Spectrometer (NGIMS) to determine the role that the “loss to space” of volatile compounds, such as CO2, NO2 and H2O, from the Mars atmosphere has played over time, giving insight into the history of the Martian atmosphere and climate, liquid water and planetary habitability.

Next Generation Weather Satellite

If you are looking for something closer to home, NASA launched the National Polar-orbiting Operational Environmental Satellite System (NPOESS) on November 4, 2011. This is a next- generation weather satellite.

One of the five analytical instruments the satellite carries is the Cross-track Infrared Sounder (CrIS), a Fourier transform spectrometer with 1305 spectral channels, which will produce high-resolution, three-dimensional temperature, pressure and moisture profiles.

These profiles will be used to enhance weather forecasting models, and they will facilitate both short- and long-term weather forecasting. Over longer time frames, they will help improve understanding of climate phenomena such as El Niño and La Niña.

Gas Chromatography: To Infinity and Beyond was posted at Materials Analysis Provider Innovatech Labs Newsroom – Innovatech Labs. | http://www.innovatechlabs.com/newsroom

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Following are a few FTIR sampling methods used by university researchers, scientists and process engineers alike.

Attenuated Total Reflectance (ATR)

In Attenuated Total Reflectance (ATR) spectroscopy, all that is required for analysis is that the sample of interest be brought into contact with the ATRcrystal. Minimal to no sample preparation is required for this technique; you can analyze a wide variety of solids and some liquids (dependent upon crystal material) using this technique.

Specular Reflectance (SR)

Specular Reflectance typically occurs from bulk samples with a glossy surface such as crystal faces, glasses, and monolithic polymers. Absorbance spectra may be obtained from specular reflection data using the Kramers-Kronig transform if the sample is homogeneous, optically thick, and if spectra are collected at a nearly normal incidence.

Reflection-Absorption (RA)

Reflection absorption occurs when thin films are present on a reflective substrate. Samples such as thin polymer films, residues and paints are suitable for reflection-absorption measurements, if they are present as an over layer on a reflective substrate.

Transmission (TR)

Transmission spectroscopy involves passing infrared radiation completely through a sample and measuring the extent of absorption. Consequently, significant sample preparation may be required as concentration, thickness, homogeneity and particle size must all be considered. This technique is suitable for sampling gases, liquids, and solids (fibers, microtome cuts, thin films, pressed pellets, and mulls).

Photoacoustic (PA)

Photoacoustic spectroscopy (PAS) can be quite complex and difficult to perform. The photoacoustic signal is generated when the infrared radiation absorbed by a sample is converted to heat within the sample. This heat diffuses to the sample surface and into the adjacent gas atmosphere. The thermal expansion of this gas produces the photoacoustic signal.

Understanding a Material’s Structure

Different levels of sample preparation are required depending on the analysis, from minimal preparation forATRto the most complex and difficult to perform, as with PA.

Understanding a material’s structure, how that structure determines its properties and how that material works in a technological application is essential for today’s engineers to be able to apply advanced surface and structural characterization techniques for quality assurance, contamination control and process improvement.

FTIR Sampling Techniques was posted at Materials Analysis Provider Innovatech Labs Newsroom – Innovatech Labs. | http://www.innovatechlabs.com/newsroom

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Following is a breakdown of what we think to be some of the best resource materials to learn more about FTIR, in particular, and spectroscopy, in general.

FTIR Tutorials

We don’t judge a book by its cover, and we don’t judge a website based on its lack of bells and whistles. We recognize that researchers and technicians are busy being, well, researchers and technicians, so we don’t expect too much in terms of Web design.

This simple, one-page website provides links to recommended books available for purchase on Amazon.com. These books cover everything from advances in infrared group frequencies to the fundamentals of molecular spectroscopy.

An added bonus is the inclusion of a number of Web links to online magazines, articles and tables.

Reference Books & Manuals

Some of the best reference material comes from industry labs within companies who supply our industry with products and services. For example, Sigma Aldrich provides an extensive learning center available on its website. Specifically, they offer an FT-IR Library which is an essential reference for

• Researchers and technicians in chemistry and biochemistry
• Undergraduate and graduate students
• Teachers and instructors
• Scientific libraries

In addition, their spectroscopy books cover titles on not only Infrared, Raman and NMR spectroscopy, but also Mass Spectroscopy, Fluorescence Spectroscopy and general Spectrophotometry.

FTIR Software & Database Bundles

Fiveash Data Management provides a complete program for handling Fourier Transform Infrared data with their FTIR software. With more than 30,000 FTIR spectra available, the software is excellent for everyday library searching and offers

• A free viewer for infrared data
• A free search program for FDM FTIR Reference Spectra Databases
• Easy-to-use complex data manipulations
• Powerful batch processing automates repetitive tasks
• Scalability, from teaching lab to on-line process environment
• Expandability, using the powerful open-source Python programming language
• Data read and written in industry-standard file formats
• Data collected directly from supported instruments
• and more.

Database bundles and a 14-day free library research trial are also available.

Expanding Your Sphere of Influence

It’s been said that knowledge is power. We believe that students and researchers, teachers and scientists have a greater opportunity to expand their knowledge and extend their influence beyond the lab with the resources available today.

Resource Materials to Learn More About FTIR was posted at Materials Analysis Provider Innovatech Labs Newsroom – Innovatech Labs. | http://www.innovatechlabs.com/newsroom

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Manufacturers stand to lose millions of dollars in lost time and product if their adhesives or solvents, for example, are contaminated. Plastics and electronics manufacturers rely on FTIR testing to determine if their polymer based parts meet their specifications and quality standards.

Forensic Chemists: The CSI of Manufacturing Processes

Lab analysts, the forensic scientists of the business world, examine objects, substances and chemicals just like criminologists do. It’s just that they deal with data retrieved from a manufacturing process rather than a crime scene.

The data or “evidence” collected at the plant is subsequently analyzed in a laboratory by scientists specializing in materials characterization.. While FTIR analysts don’t identify fingerprints or DNA, they do identify unknown materials, residues, films and fibers, just like crime scene technicians. In a way, you could consider them to be forensic chemists.

The similarities don’t end there. Just as the presence of more people at the scene of the crime introduces a greater likelihood of contaminating evidence, multiple handlings of industry samples may degrade the the data obtained. Often, samples extracted from an object or solution contain minute amounts of the chemical of interest and require very sensitive and accurate instruments for analysis, strict quality controls must be imposed to avoid misidentification.

FTIR Identifies  Materials

We use Fourier Transform Infrared Spectroscopy (FTIR) as a materials analysis and characterization technique to identify organic (and in some cases inorganic) materials.  Large reference libraries of the FTIR spectra of commercially available materials allow the analyst to identify unknown materials.  Using the use a microscope attachment to the FTIR, small particles or fibers down to 20 microns in size can be identified.

FTIR testing is also able to assist in the following types of analyses:

• Measure levels of oxidation or degree of cure in polymers.
• Quantify amounts of certain contaminants present on a material.
• Identify constituents of a multi-layered material.

FTIR Testing Improves Profitability

FTIR analysts may not sound as glamorous as crime scene investigators, and we don’t typically wear low cut shirts under our lab coats, but when you realize the amount of money and lost time involved in an unusable  product, that’s enough to get and keep any CEO’s attention. FTIR testing then becomes a critical component to your bottom line.

CSI Miami Meets Minnesota’s Forensic Chemists was posted at Materials Analysis Provider Innovatech Labs Newsroom – Innovatech Labs. | http://www.innovatechlabs.com/newsroom

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Ion chromatography (IC), also called ion exchange chromatography, is a cleanliness-testing technique that involves the separation of anions or cations. This separation is accomplished through the use of high performance liquid chromatography (HPLC), which is based on the separation of the components of a mixture in solution by selective absorption. The ions in a sample are moved through the system by an ionic solution (eluent – the mobile phase), and then the various ions are separated in a column with an ion-exchange resin (stationary phase). The resin’s surface layer has limited ion-exchange sites that attract either anions or cations. A detector at the end of the column measures the quantity of exiting ions, and from this data a chromatogram is produced.

Steps in the IC process:

1. Sample preparation – The sample or components of interest must be suspended in solution.  In many cases, a solid sample will be extracted with ultra pure water to remove any ionic species present.
2. Feed injection – The sample or water from the extraction of the sample is injected into the carrier fluid.
3. Separation – Ionic separation of the sample takes place.
4. Exiting of components – The components exit (elude) from the column, beginning with those least bound to the stationary phase. The time it takes for each species to pass through the system is unique to that species.
5. Detection – The eluded components are analyzed by measuring the change in conductivity, UV absorbance or refractive index of the eluent as the separated ionic species pass through the detector.
6. Chromatogram – A chromatogram is produced that plots the peaks representing sample components.

Generally, the IC testing, from set-up to final analysis, takes about an hour.

Ion chromatography analysis can be used for both qualitative and quantitative determinations. Material identification – that is, determining the presence of specific anions and cations in a sample – is achieved by comparing sample chromatograms against known reference-material results. And quantitation – that is, quantifying anion and cation concentrations – is accomplished by comparing each anion’s or cation’s peak height in the chromatogram to a standardization curve of each species’ known concentrations.

Additional applications of Ion Chromatography:

• Analysis of water for pollution and contaminants (both water for human consumption and aquatic ecosystems)
• Determining additive and sugar/salt content in foods
• Isolating selected proteins

The chief advantage of IC for separation of samples is that it is easy, fast, and sensitive, especially in detecting and plotting concentrations of inorganic anions and cations. And further development and improvement of this method is ongoing, with several new applications on the horizon.

IC testing, can be an indispensable tool for cleanliness testing to ensure quality control:  a tool that can be used to complete the manufacturing process before products ship to market. It is the only available technique that allows for quantitative analysis of anions and cations at the level of parts per billion (ppb).

Ion Chromatography for Quality Control was posted at Materials Analysis Provider Innovatech Labs Newsroom – Innovatech Labs. | http://www.innovatechlabs.com/newsroom

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What is GC/MS?

To ensure product quality and consumer safety, many manufacturers turn to Gas Chromatography/Mass Spectrometry (GC/MS). Combining aspects of both gas-liquid chromatography and mass spectrometry, GC/MS is a materials-analysis technique used to perform a specific test to positively identify a specific substance in a sample. Consequently, it is also considered the “gold standard” for forensic substance identification.

How do you analyze a Sample?

In the GC/MS process, a sample is first injected into a gas chromatograph, where components are separated according to size and/or polarity. Then, the components pass into a device known as a mass selective detector. It’s at this stage that a mass spectrum is obtained and compared against standard reference libraries in order to identify unknown components in the sample.

At best, a non-specific test can only statistically suggest the identity of a substance in a sample, which sometimes results in false positives. GC/MS, however, is a specific test and can, as a result, be used to positively identify the actual presence of unknown substances in a sample. Either gaseous or liquid samples, as small as several micro-liters, can be analyzed. And the whole process of GC/MS takes about one hour or less, depending on the complexity of the compound to be analyzed.

The two major components of GC/MS are the gas chromatograph and the mass spectrometer. Utilizing a capillary column with critical dimensions and phase properties, the gas chromatograph allows the different molecules of a sample to separate as the sample travels through the column. The mass spectrometer, downstream from the gas chromatograph, breaks each molecule into ionized fragments, which are then detected according to their mass-to-charge ratio. And because these two components of the process are working together, accurate substance identification is possible. Combining the two processes, gas chromatography and mass spectrometry, decreases the possibility of error and increases certainty that a particular analyte is in the sample.

GC/MS Applications

When the materials-analysis job calls for a specific test to positively identify a specific substance or substances in a sample, GC/MS is the usually the tool of choice. For this reason, it finds several applications in manufacturing – for example, detection and identification of residual solvents, trace impurities in liquids, and sealed-environment atmospheric impurities. GC/MS is also used extensively in forensics – fire investigation, drug detection, explosives investigation, and environmental analysis.

Specific Substance Testing: The Definitive Guide to GC/MS was posted at Materials Analysis Provider Innovatech Labs Newsroom – Innovatech Labs. | http://www.innovatechlabs.com/newsroom

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