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Chemical Testing Capabilities
The following methods are used by West Penn Testing Group to conduct spectrochemical testing. See the terms below in the glossary to learn more about a particular type of testing:
- Optical Emission Spectrograph (OE)
- LECO C/S/N/O/H
- Graphite Furnace Atomic Absorption (GFAA)
- Ion Chromatograph (IC)
- Optical Emission Spectrometer (OES)
- X-ray Fluorescence (XRF)
- Inductive Coupled Plasma (ICP)
- Direct Current Plasma (DCP)
- Portable XRF Analyzer - Supports Chemical Analysis in the Field
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Equipment
West Penn Testing Group maintains and operates the following chemical testing equipment in our facilities. Click on any of the items below to learn more about our equipment:
- X-ray Spectrometers
- Phillips 2400
- ICP Plasma Emission
- Leemans PS1000
- Gas Analyzers
- Leco TC-136
Leco RH-402
- Carbon Sulfur
- Leco CS-444
- Atomic Absorption
- PE5100ZL
- Thermo Gravimetric
- Leco TGA-601
- Ion Chromatograph
- Dionex IC 90
- Optical Emission
- Spectromaxx
ARL 2 Meter Spectrograph
Chemical Testing Services
West Penn Testing Group provides clients with a comprehensive range of chemical testing services. Our state-of-the-art labs are configured to handle large and small samples. For more than 50 years, our organization has provided chemical testing and material analysis to the defense, aerospace, automotive, glass refractory ceramics and metals industries. West Penn Testing Group is ISO and NADCAP accredited, and maintains compliance with more than 500 industry and individual client testing specifications.
Chemical Testing Glossary Terms
Optical Emission Spectrograph (OES)
uses a spark source to excite a metallic sample. Elements absorb excess energy from the spark and then transition back to lower energy states, giving off light at specific wavelengths. Samples must be solid metallics and have a smooth clean surface. 10 different base metals can be analyzed for most alloying elements including carbon, sulfur and nitrogen.
| LECO
equipment uses combustion methods to determine carbon, sulfur, nitrogen, oxygen and hydrogen in metals and inorganics. Samples are combusted and the resulting gasses are passed through detectors to measure each element.
| Graphite Furnace Atomic Absorption (GFAA)
utilizes samples that are dissolved in acid and then injected into a small electrically heated graphite tube. The sample is dried and analyzed by vaporizing at high temperature. The vapors are then passed through a light beam that uses absorbance to measure concentration, specifically very low levels of metallic elements.
| Ion Chromatograph (IC)
analysis begins with samples that are leached or dissolved in water and the liquid solution is injected into an analytical column. The solution is pumped through the column and “elutes” different anions through at different speeds, allowing them to be separated and measured by conductivity. Commonly determines fluoride, chloride, nitrate, phosphate and sulfate.
| Optical Emission (OE)
analysis entails mixing samples with conductive material and exposing them to a spark. After passing the light through a spectrometer, the resulting light is captured on film and developed By checking an elements characteristic wavelengths on the film, it can be qualitatively determined if an element is present in the sample.
| X-ray Fluorescence (XRF)
samples are prepared by grinding or fluxing in glass and exposed to high power x-rays. Radiation is reflected at specific wavelengths depending on the composition of the material, allowing individual elements to be quantified.
| Inductive Coupled Plasma (ICP)
involves dissolving samples in acid and aspirating them into an argon plasma. Elements absorb excess energy from the plasma and then transition back to lower energy states, giving off light at specific wavelengths. The intensity is measured with a photomultiplier tube and is proportional to the concentration of the element present.
| Direct Current Plasma (DCP)
dissolves samples in acid and aspirates them into a slightly different plasma than ICP. Elements absorb excess energy from the plasma and then transition back to lower energy states, giving off light at specific wavelengths. A DCP has better detection limits than ICP for alkalis, specifically lithium and sodium.
Common Inorganic Reporting Terms
Basis
This refers to the state in which results are reported. Typically Calcined Basis, As Received Basis, Dry Basis.
| Calcine
To heat a sample to a high temperature so as to drive off all moisture and waters of hydration, as well as most carbon such as free carbon, carbonates and organic carbon, but at a temperature below the material’s melting point. Also commonly referred to as ashing a sample. Metallic elements tend to be oxidized to their most fully oxidized state during this process. During this process, Moisture and LOI may be determined. The most common temperature to heat to is 950°C. Calcining is not to be done to glass samples. Material that has been calcined is reported on a “Calcined Basis” or “On Calcined”. [calcining is necessary to remove harmful species from the samples prior to fusing in lithium tetraborate for XRF analysis. Calcining will not remove the following trouble compounds: Silicon Carbide, ferroalloys, lead and some other heavy metals. Any of these at levels above trace can destroy the platinum–gold crucibles used to prepare fused beads.]
| Drying
Heating a sample to 105°C to a constant weight for the purpose of driving off all free moisture. Used to determine Moisture, reported on an As Received Basis. Tests performed on a sample that has been dried is reported on a “Dry Basis.”
| As Received Basis
Results calculated or determined based on the physical state the sample was received in the lab. Sample may be crushed, etc, but not dried or calcined. Typically used in conjunction with glass samples. Testing is reported on an “As received” basis. If all testing is as received, no basis may be specified, and “As Received” should be assumed.
| Loss on Ignition (LOI)
The loss in weight percent a sample exhibits when heated to high temperature, typically 950°C. When reported alone, it is reported on an “As Received Basis” and is the loss from ambient to the specified temperature. When reported with a Moisture value, the LOI will typically be reported on a dry basis and is the loss from 105°C to the specified temperature.
| Gain on Ignition (GOI)
The same procedure as LOI, but resulting in a gain. May also be reported as a negative LOI. Common when a sample contains little carbon and hydrated waters, but has species which become more oxidized during the calcining step, as metallic iron to ferric oxide.
