Sample preparation for ICP

Jarvis, I. (1992) Sample preparation for ICP-MS. In Handbook of Inductively Coupled Plasma Mass Spectrometry (eds K. E. Jarvis, A. L. Gray, and R. S. Honk), Blackie, Glasgow, pp. 172-224. 

Sample preparation for analysis by hyphenated methods requires some additional planning when compared to nonhyphenated methods. All steps, extraction, concentration, and final solvent selection must take into consideration and be compatible with all the components of the hyphenated instrumentation. For gas chromatographic methods, all the components in the mixture must be in the gaseous state. For liquid chromatography (LC) or high-performance liquid chromatography (HPLC), the samples of the analytes of interest can be solids or liquids, neutral or charged molecules, or ions, but they must be in solution. If the follow-on analysis is by MS, then each of the analytes may require a different method of introduction into the MS. Metals and metal ions may be introduced by HPLC if they are in solution but commonly are introduced via AAS or inductively coupled plasma (ICP). Other analytes may be directly introduced from HPLC to MS [2],... 

Solid samples are digested for total metal analysis with hot nitric acid and hydrogen peroxide according to EPA Method 3050. The addition of hydrochloric acid is optional. There are two different digestion protocols within this method, one for FLAA and ICP-AES analyses and the other for GFAA analysis. These two procedures are not interchangeable, and for this reason samples prepared for FLAA or ICP-AES analysis must not be analyzed with GFAA methods. 

The analysis of the silver content in the silver compositions of this invention may be done by atomic absorption (AA), inductively coupled plasma/atomic emission (ICP/AES), or other techniques known to one of ordinary skill in the art to be sensitive to silver in the appropriate concentration range. If the particles of the silver composition are small and uniformly sized (for example, 0.01 micrometers or less), a reasonably accurate assay may be obtained by running the colloid directly by AA or ICP/AES. This is because the sample preparation for AA ionizes essentially all of the silver allowing its ready detection. 

There are still a good deal of art and experience as well as science required for development of successful ICP-MS methods. A huge database of specific sample preparation and ICP-MS analysis procedures is available in the literature and should be consulted before beginning the analysis of samples. Many of the instrument manufacturers maintain databases of downloadable methods and technical reports on their web sites. Despite the low detection limits and high selectivity of ICP-MS, preconcentration or separation of sample components before analysis may be required. Numerous articles describing new analysis approaches using ICP-MS continue to be published. 

Sample Preparation for Speciation Analysis by Liquid-Phase Separation Techniques Coupled with ICP-MS... 

In order to reduce possible contamination problems during sample preparation, LA-ICP-MS is applied for the precise and accurate determination of isotope ratios at the trace and... 

Knapp, G. Development of mechanized sample preparation for plasma emission spectrometry. ICP Inf Newsl. 10, 91-104 (1984)... 

The ashing of plywood was carried out according to ASTM standard (D 3174-89). The sample preparation for the ICP- and DCP-AES determinations were carried out according to ASTM standard (D 3682-97) by mixing the bed samples or... 

The first step in analysing plastics for metals content in polymers by ICP-AES technique is that they must be prepared in solutions that are suitable for nebulization. There are four general methods applicable for sample preparation for metal analysis by ICP-AES and they are solvent dissolution of some plastics dry ashing using a muffle furnace acid digestion using a microwave oven and oxygen bomb combustion. 

Analysis of urine samples for metals content is a useful way to study the presence of toxic metals in humans. The metal content can give an indication of the performance of kidneys in regulating the body electrolyte, water metabolism and rate of excretion of metals from the body. ICP-OES can be used to measure the level of heavy metals in urine of both healthy and pathological cases. Sample preparation for analysis of these samples must involve an acid digestion in a microwave oven or bomb combustion to destroy the interfering organics present. Metals such as Pb, Cd, Tl, Se, Sn and Hg are the usual metals requiring analysis. 

The first requirement can be easily fulfilled by the preconcentration of the analyte before the analysis. Preconcentration has been applied to sample preparation for flame atomic absorption (25) and, more recently, for ICP (79,80) spectroscopy. However, preconcentration is not completely satisfactory, because of the increased analysis time (which may be critical in clinical analysis) and the increased chance of contamination or sample loss. Most important, however, a larger initial sample size is necessary. The apparent solution is a more sensitive technique. Table 2 lists concentrations of various metals in whole blood or serum (81,82) in comparison to limits of detection for the various atomic spectroscopy techniques. In many cases, especially for the toxic heavy metals, only flameless atomic absorption using a graphite furnace can provide the necessary sensitivity and accommodate a sample of only a few microliters (Table 1). The determination of therapeutic gold in urine and serum (83,84), chromium in serum (85), skin (86) and liver (87), copper in semen (88), arsenic in urine (89), manganese in animal tissues (90), and lead in blood (91) are but a few examples in analyses which have utilized the flameless atomic absorption technique. 

The analysis data of few selected catalyst samples, generated very carefully in triplicate by ICP, were used for calibration of XRF instrument (SRS 3000, Siemens Germany). After calibrating the instrument with quantitative software, the catalyst samples were analyzed as such without any sample preparation. For precision study, four catalyst samples were analyzed five times in different days. During each analysis, five consecutive measurements were made the results averaged. 

Sample preparation for the determination of trace concentration levels of the many priority pollutant metals is strongly connected to the nature of the determinative technique. Historically, FIAA was first used to measure metals. The more sensitive GFAA technique followed. Along about the same time as GFAA was being developed, ICP-AES came along. ICP-AES afforded the opportunity to measure more than one metal in a sample at a time, the so-called multielement approach. In recent years, the development of ICP-MS has carried trace metal analysis to significantly lower IDEs and introduced the opportunity to identify and to quantitate the various elemental isotopes. 

Abstract Heavy elements inevitably contaminate the effluents from surface finishing industries. Determination of the elements is important to estimate the level of contamination and thus proceeds for treatment of the effluents. We offer two types of instmments ICP-AES, and ICP-MS for determination of the elements. The atomic absorption spectrometer requires an individual lamp for each element to be determined, whereas the ICP-MS offers multi-elemental analysis. For both, ICP-AES and ICP-MS, the apparatus required is to be cleaned in 5 % sodium hydroxide, 5 % nitric acid, and ultrapure water sequentially. Samples of effluents are taken in clean bottles, previously washed three times. All reagents and water are purchased at the ultrapure level. Standard solutions are also bought commercially, and appropriate dilutions are prepared for ICP-AES or ICP-MS. Measurements of the concentration of elements by using the ICP-AES and ICP-MS are repeated at least three times and a blank is checked simultaneously. A calibration line is calculated using 3 or 4 standard solutions and r (the slope) is ascertained, which should be near 1 to achieve accurate determinations. The concentration of elements is calculated from the calibration line and errors are estimated. 

Particle analysis of environmental samples by secondary ion mass spectrometry (SIMS, see Sect. 63.5.6.3) or scanning electron microscopy in combination with X-ray spectrometry (SEM-XRS, see Sect. 63.5.6.4). The SEM-XRS instrument and its sample-preparation area are located in the clean laboratory, but the SIMS instrument is not. Sample preparation for SIMS can be carried out in the CL, but a small dedicated clean-room at US Class-lOO/ISO-Class 5 cleanliness level is colocated with the instrument to avoid potential cross contamination when transporting the prepared sample planchets to the instrument. The SEM-XRS method is also supported in the CL by an array of optical microscopes equipped with micromanipulation systems for picking up particles of interest prior to further treatment such as chemical analysis and isotopic measurement by TIMS or ICP-MS. 

Figure 73 shows paste samples prepared for the high pressure through-flow test. Samples were cut from the cylindrical specimens and made with the two binders and two L/B ratios of 0.13 and 0.15. Paste and concrete samples from the site trials (see section 3) were also tested and compared with OPC paste. Sample solutions were collected from the specimens tested in the Hoek cell and analysed using an inductively coupled plasma (ICP) spectrometer in the chemistry department at Coventry University (Table 40). 

At present the real strength of LA lies in the measurement of distribution patterns of minor and trace elements in solid samples with high spatial resolution. Homogeneity testing is an application of LA-ICP-MS. There is an increasing demand for the development and validation of accurate and robust analytical technologies for the determination of the chemical characteristics of polymeric products in support of industrial needs, EC regulations (e.g. Directive on toy safety) or research. Needs are particularly acute for techniques able to determine trace element contents in solids with a minimum sample preparation. For this purpose, laser ablation-based methods, such as LA-ICP-AES/MS and laser-induced plasma atomic emission spectrometry (LIP-AES, LA-AES or LIBS) have already... 

Flow injection (FI) is a powerful front-end sampling accessory for ICP-MS that can be used for preparation, pretreatment, and delivery of the sample. Originally described by Ruzicka and Hansen, FI involves the introduction of a discrete sample... 

Arunachalam,., Mohl, C., Ostapczuk, P., and Emons, H. (1995). ICP-MS evaluation of continuous-flow sample preparation for the determination of lead in environmental samples. Multielement characterization of soil samples with ICP-MS for environmental studies. J. Res. Natl. Inst. Stand. Technol. 100(3), 316. 

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