Atomic spectrometric determinations

Bermejo-Barrera et al. [64] studied the use of lanthanum chloride and magnesium nitrate as modifiers for the electrothermal atomic spectrometric determination of p,g/l levels of arsenic in seawater. 

Normally, for determination in biological samples, the sample is digested in an oxidizing acid mixture followed by atomic spectrometric determination. Organotin can be extracted from biological samples and determined by atomic spectrometric methods or gas chromatography, usually after derivatization. 

M. de la Guardia, A. Salvador, P. Bayarri, R. Farre, Rapid atomic spectrometric determination of sodium, potassium, calcium and magnesium in powdered milk by direct dispersion, Analyst, 111 (1987), 1375-1377. 

M. D. Mingorance, M. L. Perez-Vazquez, M. Lachica, Microwave digestion methods for the atomic spectrometric determination of some elements in biological samples, J. Anal. Atom. Spectrom., 8 (1993), 853-858. 

Starn T. K. and Hieftje G. M. (1993) A gas-sampling glow discharge coupled to hydride generation for the atomic spectrometric determination of arsenic, Spectrochim Acta, Part B 48 1207-1220. 

FIGURE 6.22 A HGA used for the atom spectrometric determination of trace elements in solid or dissolved samples. The graphite tube is connected as resistor between two graphite contact cylinders. Quartz window seals are attached to both ends of the primary beam plane, and the entire unit is water cooled. 

A.N. Anthemidis, M. Miro, Recent developments in flow injection/sequential injection liquid-liquid extraction for atomic spectrometric determination of metals and metalloids, Appl. Spectrosc. Rev. 44 (2009) 140. 

The methodologies used for chromium speciation in liquid samples are very diverse preconcentration on different types of columns, chemical reactions such as complexation or oxidation-reduction, and other separation procedures have been used and will be reviewed briefly below. These pretreatments with subsequent atomic spectrometric determination allow good limits of detection and recoveries for samples with low concentrations of chromium (Comelis 1996). Polarography is also suitable for the determination of chro-... 

H Matusiewicz, RE Sturgeon. Atomic spectrometric determination of hydride forming elements following in situ trapping within a graphite furnace. Spectrochim Acta B 51 377-397, 1996. 

Gas-diffusion separations may be further divided into single and dual-phase separation systems. Single-phase systems are used for spectrophotometry, electrochemistry and chemiluminescence etc., with which liquid phase is used in both donor and acceptor channels. Dual-phase systems use a suitable gas as the acceptor stream, while the donor stream is liquid such systems are used with mass spectrometric (cf. Sec. 5.4.6) or electron capture detection [7J, but may also be used as a substitute for gas expansion separation in vapK>ur generation atomic spectrometric determinations (cf. Sec. 5.5.1 FI hydride generation manifolds with dual phase gas diffusion separators)... 

Morales-Rubio A, Salvador A, de al Guardia M. 1992. Microwave muffle furnace assisted decomposition of vegetable samples for flame atomic spectrometric determination of calcium, magnesium, potassium, iron, manganese and zinc. Fresenius Journal of Analytical Chemistry 342(4-5) 452 56. 

Figure 4.65 Logical flowchart for choosing which atomic spectrometric determinative technique to use.

Table 4.19 IDLs for the Most Common Atomic Spectrometric Determinative Techniques in ppb...

Today atomic spectrometric methods are sufficiently sensitive and selective so that they are the method of choice for the determination of beryllium. These techniques can be applied directly to acid digests of biological samples. Electrothermal atomization is better suited than flame atomization for the determination of the low concentrations of beryllium usually found in clinical specimens. A review of different techniques for the atomic spectrometric determination of beryllium was recently published [32]. 

Anthemidis, A. N. and N. P. Kalogiuri. 2013. Advances in on-line hydride generation atomic spectrometric determination of arsenic. Anal. Lett. 46 1672-1704. 

A flow-injection system with electrochemical hydride generation and atomic absorption detection for the determination of arsenic is described. This technique has been developed in order to avoid the use sodium tetrahydroborate, which is capable of introducing contamination. The sodium tetrahydroborate (NaBH ) - acid reduction technique has been widely used for hydride generation (HG) in atomic spectrometric analyses. However, this technique has certain disadvantages. The NaBH is capable of introducing contamination, is expensive and the aqueous solution is unstable and has to be prepared freshly each working day. In addition, the process is sensitive to interferences from coexisting ions. 

Elements with 1 predominant isotope can also, potentially, permit very precise atomic weight determinations since variations in isotopic composition or errors in its determination have a correspondingly small effect on the mass-spectrometrically determined value of the atomic weight. Nine elements have 1 isotope that is more than 99% abundant (H, He, N, O, Ar, V, La, Ta... 

Braman and Tompkins10 developed the atomic emission spectrometric determination method for the determination of inorganic and organic germanium compounds in the... 

Elemental analysis can be performed at ultratrace levels with any atomic spectrometric technique and the final selection is based on the identity and the number of elements to be determined. The initial step that is common to all analyses by atomic spectroscopy is the generation of a homogeneous solution. 

A convenient method is the spectrometric determination of Li in aqueous solution by atomic absorption spectrometry (AAS), using an acetylene flame—the most common technique for this analyte. The instrument has an emission lamp containing Li, and one of the spectral lines of the emission spectrum is chosen, according to the concentration of the sample, as shown in Table 2. The solution is fed by a nebuhzer into the flame and the absorption caused by the Li atoms in the sample is recorded and converted to a concentration aided by a calibration standard. Possible interference can be expected from alkali metal atoms, for example, airborne trace impurities, that ionize in the flame. These effects are canceled by adding 2000 mg of K per hter of sample matrix. The method covers a wide range of concentrations, from trace analysis at about 20 xg L to brines at about 32 g L as summarized in Table 2. Organic samples have to be mineralized and the inorganic residue dissolved in water. The AAS method for determination of Li in biomedical applications has been reviewed . 

An alternative to AAS is the more sensitive spectrometric determination of Li by inductively coupled plasma atomic emission spectrometry (ICP-AES) or optical emission spectrometry (ICP-OES). In Table 3 are summarized the spectral lines of the Li emission... 

Manganese in aqueous solution may be analyzed by several instrumental techniques including flame and furnace AA, ICP, ICP-MS, x-ray fluorescence and neutron activation. For atomic absorption and emission spectrometric determination the measurement may be done at the wavelengths 279.5, 257.61 or 294.92 nm respectively. The metal or its insoluble compounds must be digested with nitric acid alone or in combination with another acid. Soluble salts may be dissolved in water and the aqueous solution analyzed. X-ray methods may be applied for non-destructive determination of the metal. The detection limits in these methods are higher than those obtained by the AA or ICP methods. ICP-MS is the most sensitive technique. Several colorimetric methods also are known, but such measurements require that the manganese salts be aqueous. These methods are susceptible to interference. 

The contribution of flow analysis to improving the performance of atomic spectrometry is especially interesting in the field of standardisation. FIA can provide a faster and reliable method to relate the absorbance, emission or counts (at a specific mass number) to the concentration of the elements to be determined. In fact, flow analysis presents specific advantages to solving problems related to the sometimes short dynamic concentration ranges in atomic absorption spectrometry, by means of on-line dilution. The coupling of FI techniques to atomic spectrometric detectors also offers tremendous possibilities to carry out standard additions or internal standardisation. 

S. Cancela and M. C. Yebra, Flow-injection flame atomic absorption spectrometric determination of trace amounts of cadmium in solid and semisolid milk products coupling a continuous ultrasound-assisted extraction system with the online preconcentration on a chelating ami-nomethylphosphoric acid resin, J. AO AC Int., 89(1), 2006, 185-191. 

M. C. Yebra, A. Moreno-Cid, R. Cespon and S. Cancela, Preparation of a soluble solid sample by a continuous ultrasound assisted dissolution system for the flow-injection atomic absorption spectrometric determination of iron in milk powder and infant formula, Talanta, 62(2), 2004, 403 406. 

M. C. Yebra-Biurrun, A. Moreno-Cid and L. Puig, Minicolumn field preconcentration and flow-injection flame atomic absorption spectrometric determination of cadmium in seawater, Anal. Chim. Acta, 524(1-2), 2004, 73-77. 

C. Moscoso-Perez, J. Moreda-Pineiro, P. Lopez-Mahia, S. Muniategui-Lorenzo, E. Fernandez-Fernandez and D. Prada-Rodriguez, Hydride generation atomic fluorescence spectrometric determination of As, Bi, Sb, Se(tV) and Te(IV) in aqua regia extracts from atmospheric particulate matter using multivariate optimisation, Anal. Chim. Acta, 526(2), 2004, 185-192. 

P. Bermejo-Barrera, A. Moreda. Pineiro and A. Bermejo-Barrera, Factorial designs for Cd, Cr, Hg, Pb and Se ultrasound-assisted acid leaching from human hair followed by atomic absorption spectrometric determination, J. Anal. At. Spectrom., 15(2), 2000, 121-130. 

G. A. Zachariadis and J. A. Stratis, Optimisation of cold vapour atomic absorption spectrometric determination of mercury with and without amalgamation by subsequent use of complete and fractional factorial designs with univariate and modified simplex methods, J. Anal. At. Speetrom., 6(3), 1991, 239-245. 

Photoionization mass spectrometric studies, by Berkowitz and coworkers, of SiH2 formed by successive abstraction of H atoms from SiH4 by F atoms allowed determination of the ionization potentials of the two lowest states 1Ai(5o) = 9.15 0.02 or 9.02 0.02 eV and 3Bi(Ji) = 8.244 0.025 eV299. This important series of experiments300 yielded a singlet-triplet separation for SiH2 of either 0.78 0.03 or 0.91 0.03 eV. 

Atomic spectrometric methods Here, the entire sample is atomized or ionized either by flame or inductively coupled plasma and transferred into the detector. The most common techniques in this class are flame atomic absorption spectrometry (FAAS) and inductively coupled plasma mass spectrometry (ICPMS). A general characteristic of these methods is the determination of the total concentration of the analyte without the direct possibility of distinguishing its specific forms in the sample. 

Liang, P. and Liu, R. (2007) Speciation analysis of inorganic arsenic in water samples by immobilized nanometer titanium dioxide separation and graphite furnace atomic absorption spectrometric determination. Analytica Chimica Acta, 602(1), 32-36. 

An atomic fluorescence spectrometric determination of selenium was first reported by Dagnall et al. [185] using a dispersive spectrometer equipped with an air-propane flame, giving a detection limit of 0.25 xg/ml of selenium on aspiration of aqueous solutions using a pneumatic nebuliser. Fluorescence from the 204 nm selenium resonance line was observed when the flame was irradiated by radiation from a selenium electrodeless discharge lamp, the optical axis of which was aligned at 90 °C to the optical axis of the monochromator. 

---