Steel trace analysis

Nickel, in stainless steel, reproducibility of determination, 256 trace analysis by x-ray emission spectrography, 228-232... 

The application of SIMS, SNMS, SSMS and GDMS in quantitative trace analysis for conducting bulk material is restricted to matrices where standard reference materials (SRMs) are available. For quantification purposes, the well characterized multi-element SRMs (e.g., from NIST) are useful. In Table 9.5 the results of the analysis by SNMS and the RSCs (relative sensitivity coefficients) for different elements in a low alloy steel standard (NBS 467) are compared with those of SSMS. Both solid-state mass spectrometric techniques with high vacuum ion sources allow the determination of light non-metals such as C, N, and P in steel, and the RSCs for the elements measured vary from 0.5 to 3 (except C). RSCs are applied as a correction factor in the analytical method used to obtain... 

Plastic containers must be washed before use. Table 28-1 shows that manganese in blood serum samples increased by a factor of 7 when stored in unwashed polyethylene containers prior to analysis. In the most demanding trace analysis of lead at 1 pg/g in polar ice cores, it was observed that polyethylene containers contributed a measurable flux of 1 fg of lead per cm2 per day even after they had been soaked in acid for 7 months.4 Steel needles are an avoidable source of metal contamination in biochemical analysis. 

Contamination is a problem one always faces in trace analysis. Mercury is ubiquitous in many laboratories, as is fluoride. Lead is present in dust, particularly in laboratories located close to heavy automobile traffic. Extreme caution must always be exercised as contamination on the trace level may come from unexpected sources. Table I shows that using manganese steel in the jaws used to crush the coal increased the manganese content of the crushed coal more than twofold. 

When the graphite furnace is used for extreme-trace analysis, relative standard deviations are in general above 10 relative percent. The solid sample analysis described in section II.B.l, using a steel chip and the rectangular cuvette, leads to an RSD of 13 relative percent in the determination of a... 

All of the usual precautions for trace analysis must be taken. Corrosion of steel parts in contact with the eluent must be avoided, since the presence of Fe can seriously interfere. The eluent substances, in addition, must not contain complex-forming substances. 

Although AAS is predominantly used as a technique for trace analysis, it has also been applied for the determination of main components, such as calcium in cement [21], lead and tin in soft solders [149], or chromium, iron and nickel in stainless steel [16] using... 

Although normally applied in trace analysis, a substoicheiometric isotope dilution method has been reported by McClendon and DeVoe for the determination of W at high concentration using toluene-3,4-dithiol. More recent work has applied this reagent to the measurement of tracer levels of W in steel, meteorites, and kale by an n.a.a. method. Baishya and Heslop have endorsed the use of toluene-3,4-dithiol for both isotope dilution and activation methods for the determination of W, but reject 8-hydroxyquinoline, a-benzoin oxime, and cupferron. ... 

Miscellaneous Samples Besides environmental and clinical samples, differential pulse polarography and stripping voltammetry have been used for the analysis of trace metals in other samples, including food, steels and other alloys, gasoline, gunpowder residues, and pharmaceuticals. Voltammetry is also an important tool for... 

National Institute of Standards and Technology (NIST). The NIST is the source of many of the standards used in chemical and physical analyses in the United States and throughout the world. The standards prepared and distributed by the NIST are used to caUbrate measurement systems and to provide a central basis for uniformity and accuracy of measurement. At present, over 1200 Standard Reference Materials (SRMs) are available and are described by the NIST (15). Included are many steels, nonferrous alloys, high purity metals, primary standards for use in volumetric analysis, microchemical standards, clinical laboratory standards, biological material certified for trace elements, environmental standards, trace element standards, ion-activity standards (for pH and ion-selective electrodes), freezing and melting point standards, colorimetry standards, optical standards, radioactivity standards, particle-size standards, and density standards. Certificates are issued with the standard reference materials showing values for the parameters that have been determined. 

The detection and determination of traces of cobalt is of concern in such diverse areas as soflds, plants, fertilizers (qv), stainless and other steels for nuclear energy equipment (see Steel), high purity fissile materials (U, Th), refractory metals (Ta, Nb, Mo, and W), and semiconductors (qv). Useful techniques are spectrophotometry, polarography, emission spectrography, flame photometry, x-ray fluorescence, activation analysis, tracers, and mass spectrography, chromatography, and ion exchange (19) (see Analytical TffiTHODS Spectroscopy, optical Trace and residue analysis). 

Normally one can assume that most metallic samples contain elemental traces in a homogeneous distribution. Lead, Bi, Zn, Ag and Sb in steel and nickel-base alloys were determined, first by using the graphite boat technique for routine analysis. Several calibration approaches were studied and it was found that the best results could be obtained by using various amounts of a number of solid alloyed steel or pure iron CRMs and to plot absorbance against concentration of the element sought (Backman and Karlsson 1979). 

Steele I. M., Hutcheon I. D. and Smith J. V. (1980b). Ion microprobe analysis of plagioclase feldspar (Cai xNaxAl2 xSi2+x08)- for major, minor and trace elements. VIII Int. Congr. X-ray Optics Micro analysis, Pendell Pub. Co, Midland, Michigan. 

Table 9.5 Comparison of trace element analysis on low alloy steel standard (NBS...

The primary components of the RAS are a 1-liter stainless-steel blender container, a stainless-steel jacket that water flows through, a variable-speed motor with controller, modified lid with inlet and outlet for gas flow, and a variable-area needle-valve flow meter. The large volume allows for the collection of sufficient volatiles to concentrate trace components for GC/MS analysis. Figure Gl.7.2 shows a diagram of the RAS. 

Crude material prepared in glass on 3 g mol scale was distilled uneventfully at 40°C/ 0.067 mbar from a bath at 70—80°C. A 30 mol batch prepared in a glass-lined vessel with a stainless steel thermo-probe (and later found to contain 15 ppm of iron) decomposed very violently during distillation at 75°C/13 mbar from a bath at 130°C. Thermal analysis showed that the stability of the methyl (and ethyl) ester was very sensitive to traces of heavy metals (iron, copper, chromium, etc.) and was greatly reduced. Addition of traces of hydrated iron(II) sulfate led to explosive decomposition at 25°C. 

ICP-MS has been used for the analysis of many materials, including alloys, steels, nuclear materials, ceramics, superconductors, plastics, polymers, and catalysts. Semiquantitative analysis by ICP-MS is often a convenient method to screen samples for trace elements and impurities. Measurement of impurities can be complicated by sample matrix-dependent degradation of sensitivity, particularly if the samples contain high concentrations of heavy elements that create extensive space-charge-induced ion transmission losses. Matrix matching is complicated by the need for ultrapure materials. 

ICP-MS has also been used to measure trace elements in archaeological native silver artifacts [345] in order to identify their geographical origins. The low detection limits provided by ICP-MS allowed analysis of trace elements on 3 to 15 mg of sample. The passivation of alloy steels using acid solutions has been studied by XPS measurements of the solid in combination of ICP-MS analysis of the passivation solutions [346,347]. When bullets are crushed on impact, striations cannot be used for identification. The percentage of antimony, trace element composition, and lead isotope ratios in bullets was measured for forensic evidence [348]. The lead isotope ratios were found to be the most useful evidence. 

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