Chemical & Polymer Testing Analysis Equipment(partial list)
In ICP Spectroscopy, samples are acid digested and diluted in water and aspirated into a plasma torch. The emitted light is then measured and quantified relative to known standards. ICP is a very versatile spectroscopic technique, capable of analyzing a full spectrum of samples from water samples to dissolved alloys of steel, aluminum, brass, titanium and nickel based alloys. ICP Spectroscopy is used to accurately determine the chemical composition of ferrous and nonferrous alloys as well as a variety of other samples and extracts. Our lab currently uses a SpectroFlame M120E spectrometer. The standards used for analyses are traceable to NIST.
Glow Discharge Spectroscopy (GDS)
Within the GDS the spectrometer uniformly sputters a small amount of metal from the sample surface (typically 100-200micrometers) and draws this material into an anode where a powerful electric field excites the atoms and they emit light at characteristic wavelengths. The emmitted light passes through a grating where it is dispersed and directed to a bank of photomultiplier tubes in the back of the instrument where the light is quantified.
Unlike spark spectroscopy, the surface material is not preferentially attacked which means that carbides, oxide inclusions, and sulfur and lead inclusions are uniformly removed and analyzed along with the solid solution matrix.
To analyze a sample using this instrument it must have a SMOOTH, FLAT surface at least one-half inch across. NIST traceable check standards, or secondary standards where NIST standards are not available, are used for calibration and drift correction for each alloy method
Due to difficulties in getting carbon and sulfur into solution, these elements are not readily measured by ICP Spectroscopy and an alternative technique is needed. The LECO CS-300 combustion analyzer is used for the measurement of carbon and sulfur in metals, ores, ceramic and other inorganic materials. The sample is combusted in a stream of purified oxygen which produces CO2 and SO2 from the carbon and sulfur, respectively. These species are then detected and quantified by infrared detection. The instrument is capable of detecting carbon and sulfur down to approximately 0.005% by weight in a metal sample. Standards are run with each sample which have a carbon and sulfur content as close to the sample as possible.
or: Fourier Transform Infared Spectroscopy
FTIR is a spectroscopic technique in which infrared light is passed through a sample, which has the characteristic absorption frequencies in the infrared region. This produces an infrared spectrum which looks like a series of peaks and valleys on an X-Y graph. This spectrum is unique for a given organic material and can be thought of as the material's chemical fingerprint. This technique is useful both for routine material verification/identification of polymers and identification of trace contaminates via the FTIR microscope. Micro-FTIR spectroscopy is performed on a Bio-Rad UMA-250 microscope, which is capable of obtaining spectra of objects down to about 25 microns in size. Micro-FTIR is widely used for identification of trace contaminates on manufactured items.
Gas Chromatography-Mass Spectroscopy
Gas chromatography is a technique for the separation and detection of complex mixtures of organic compounds. The separation is accomplished by means of a thin capillary column through which the sample passes in a temperature controlled oven. Ramping of oven temperature causes separation of components based on differences in volatility whereas separation based on chemical properties (i.e. polarity, acidity, etc.) is accomplished by coating the walls of the capillary column with a specific stationary phase, for which different compounds have different affinity. Compounds emerge from the capillary column as discrete bands of purified materials. Detection is accomplished with a mass spectrometer. As the separated compounds enter the mass spectrometer, they are hit by a stream of electrons, causing them to shatter into many smaller fragments which are all detected by the mass spectrometer. Unique "fingerprinting" of each compound is thus accomplished because the fragmentation pattern of each molecule is reproducible and a characteristic of the molecule. Our lab currently uses a HP 5890 Series II GC with a HP 5970 MS detector.
Scanning Electron Microscopy SEM/EDS
Scanning electron microscopy allows detailed surface analysis as well as high magnification viewing of very small features. The energy dispersive spectroscopy (EDS) feature allows the additional advantage of being able to obtain the elemental composition of small objects or surfaces. Also of particular use is when this technique is used in conjunction with Micro-FTIR for the characterization of trace contaminants and unknowns.