I ICP AES

To quantify the trace elements of interest plasma-based techniques were used, namely (i) ICP-AES using an Optima 3100 instrument (Perkin-Elmer, Norwalk, CT, USA) equipped with a cross-flow nebulizer and a Ryton Scott spray chamber (ii) Dynamic Reaction Cell (DRC) Q-ICP-MS using an Elan 6100 spectrometer (PerkinElmer, Norwalk, CT, USA) equipped with a quartz cross-flow Meinhard nebulizer and a cyclonic spray chamber (iii) SF-ICP-MS using an Elementl (ThermoElectron, Bremen, Germany) with a pneumatic nebulizer and a Ryton Scott spray chamber. 

Identification of sources of analytical bias in method development and method validation is another very important application of reference materials in geochemical laboratories. USGS applied simplex optimization in establishing the best measurement conditions when the ICP-AES method was introduced as a substitute for AAS in the rapid rock procedure for major oxide determinations (Leary et al. 1982). The optimized measurement parameters were then validated by analyzing a number of USGS rock reference samples for which reference values had been established first by classical analyses. Similar optimization of an ICP-AES procedure for a number of trace elements was validated by the analysis of U S G S manganese nodule P-i (Montaser et al. 1984). 

Similarly, some INAA data contributed to the derivation of a reference value for Ba in SDO-i were biased high by an interference from Ru (Wandless 1993). The Ru is a fission product of U, whose concentration of 40 qg/g is relatively high in SDO-1. In this case, no appropriate reference sample was available for analysis to control the SDO-1 results the interference was identified through the disagreement between INAA data and data produced using XRF and ICP-AES methods on the same sample. A bias-free method again resulted when analysis of an atypical type led to detection of a rarely encountered but sizeable spectral overlap. Once identified, correction was straightforward. 

Berman et al. [735] have shown that if a seawater sample is subjected to 20-fold preconcentration by one of the above techniques, then reliable analysis can be performed by ICP-AES (i.e., concentration of the element in seawater is more than five times the detection limit of the method) for iron, manganese, zinc, copper, and nickel. Lead, cobalt, cadmium, chromium, and arsenic are below the detection limit and cannot be determined reliably by ICP-AES. These latter elements would need at least a hundredfold preconcentration before they could be reliably determined. 

The benefits imparted by preconcentration to improved sensitivity are illustrated in the example of lead preconcentration on Chelex 100 resin [871,872], followed by analysis by ICP-AES. Without preconcentration the best detection bmit achievable is 60 ng/1, via direct nebubsation. When the Chelex 100 preconcentration step is included, the detection limit improves to 0.6 ng/1, i.e., 100 times better, which is a very important improvement achieved in the analysis of seawaters. Examinaton of Table 5.12 reveals that the following metals can be determined with detection limits in the 1 -10 ng/1 range beryllium (0.6 ng/1),... 

The determination of the total concentrations of metal ions and arsenic in the water samples and in the eluates of solid materials were carried out using ICP-AES (Spectroflame, SPECTRO A.I.) with pneumatic nebulization (cross flow). Anion (S042, Cl ) determinations were done using an ion chromatographic device with IonPac AS12A/AG12A column and a conductivity detector. 

An alternative approach is to analyze the samples using procedures or instrumentation that will give the maximum amount of data for each sample. For example, recent advances in atomic spectroscopy, i.e., inductively coupled argon plasma emission spectroscopy (ICP-AES), allow 20 to 30 elements to be detected simultaneously. 

Mercury(I) chloride may be identified from its physical properties, its reaction with ammonia to form a black product, and it may be measured quantitatively for mercury by cold vapor-AA or ICP/AES. 

Chemical composition of fresh HTs was determined in a Perkin Elmer Mod. OPTIMA 3200 Dual Vision by inductively coupled plasma atomic emission spectrometry (ICP-AES). The crystalline structure of the solids was studied by X-ray diffraction (XRD) using a Siemens D-500 diffractometer equipped with a CuKa radiation source. The average crystal sizes were calculated from the (003) and (110) reflections employing the Debye-Scherrer equation. Textural properties of calcined HTs (at 500°C/4h) were analyzed by N2 adsorption-desorption isotherms on an AUTOSORB-I, prior to analysis the samples were outgassed in vacuum (10 Torr) at 300°C for 5 h. The specific surface areas were calculated by using the Brunauer-... 

F. J. Copa-Rodriguez and M. I. Basadre-Pampin, Determination of iron, copper and zinc in tinned mussels by inductively coupled plasma atomic emission spectrometry (ICP-AES), Fresenius J. Anal. Chem., 348(5-6), 1994, 390-395. 

Figure 18.2 diagrams the workflow of a typical BE-AES experiment. There are two major experimental steps (1) buffer equilibration and (2) ICP-AES concentration determination. Both sample preparation (i.e., buffer exchange) and sample concentration determination (i.e., AES) must be successfully completed in order to make meaningful measurements. To maximize the utility of BE-AES, experimental design must carefully balance practical issues such as the availability and behavior of the nucleic acid being studied with the desire to get high precision and accuracy in the final measurements. 

Aliquots of 20—40 /iL from the top of the spin column (i.e., DNA-containing samples) and the final flow-through were added to polystyrene tubes (Fisher Science) containing 4 mL of water. It has subsequently been determined that diluting the sample in ammonium acetate buffer, pH 5.2, is superior to water. Dilution factors were such that the final concentration of all ions in the analyte remained in the linear range of ICP-AES measurements. 

Fig. 19.13. ICP-AES spectra of ion exchange resin extracts showing the relative amounts of Sr and Ca in the extracts Sr(Il) line at 421.6 nm and Ca(I) line at 422.7 nm.

Straw ash and willow ash were prepared by ashing flnely ground raw material at SSO overnight in a box furnace. The bulk composition of the ashes was determined by Inductive Coupled Plasma - Atomic Emission Spectroscopy (ICP-AES) (see Table 3). Ash was then mixed with quartz sand in a ratio of 1.3 8.7 by weight (roughly I I by volume),... 

The state of the art with respect to the potential of ICP-AES for the determination of trace elements in urine can be assessed by comparing the model concentration and range of concentrations for each of the elements (computed from the data in Table I) to the corresponding experimental limit of quantitative determination (LQD) for that element in aqueous solutions with 1% (vol) nitric acid, as is done in Table II. If the trace element concentrations in urine are as shovm in the table, and if the LQDs which can be achieved for urine samples are not substantially different from those observed for 1% nitric acid solutions, then ICP-AES should be applicable for the quantitative determination of many of the trace elements occurring in urine. 

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