Prospects in Analytical Atomic Spectrometry

Russian Chemical Reviews 75 $4) 289 ± 302 $2006) Prospects in analytical atomic spectrometry AABol'shakov, AAGaneev, V M Nemets Contents I. Introduction 289 II. Atomic absorption spectrometry 290 III. Atomic emission spectrometry 292 IV. Atomic mass spectrometry 293 V. Atomic fluorescence spectrometry 295 VI. Atomic ionisation spectrometry 296 VII. Sample preparation and introduction, atomisation and data processing 298 VIII. Conclusion 298 Abstract. The trends in the development of five main branches of processing $averaging) of noise and enhances the analysis accu- atomic spectrometry, viz., absorption, emission, mass, fluores- racy due to the use of correlation models and neural network cence and ionisation spectrometry, are analysed. The advantages algorithms. and drawbacks of various techniques in atomic spectrometry are The development of analytical spectrometry and detection considered. Emphasised are the applications of analytical plasma- techniques is stimulated by the diverse and increasing demands in and laser-based methods. The problems and prospects in the industry, medicine, science, environmental control, forensic ana- development in respective fields of analytical instrumentation lysis, etc. The development of portable analysers for the determi- are discussed. The bibliography includes 279 references.references. nation of elements in different media at the immediate point of sampling, which eliminates the stages of collecting, transportation I. Introduction and storage of samples, is one of the most important directions. It should be noted that the development of atomic spectro- Analytical atomic spectrometry embraces a multitude of techni- metry slowed down in recent years; particularly, a trend towards a ques of elemental analysis that are based on the decomposition of decreasing number of scientific publications occurred. Such a samples into the state of free atoms followed by spectroscopic deceleration could be due to the fact that the overwhelming determination of their concentrations. One can distinguish five majority of issues in elemental analysis can successfully be solved major branches of atomic spectrometry, viz., absorption, emis- using the available techniques and instrumentation. sion, mass, fluorescence and ionisation spectrometry. The first The above statements may be supplemented by several general three are most popular and versatile; atomic mass spectrometry is remarks. the most sensitive. Other methods used in elemental analysis 1. According to the amount of scientific publications and $X-ray fluorescence, nuclear magnetic resonance, Auger electron conference presentations, the inductively coupled plasma emis- spectrometry, neutron activation analysis, etc.), which are not sion and mass spectrometers $ICP-AES and ICP-MS) are the most based on the analyte atomisation and unrelated to the spectro- popular. This is because of the fact that the inductively coupled scopy of atomic vapour, are not considered in this review. plasma in argon heated to 600079000 K at the electron density of The main goals of analytical atomic spectrometry are to attain *1015 cm73 represents a virtually ideally linear atomiser and the lowest limits of detection $down to single atoms) and the ioniser $i.e., virtually independent of the sample matrix and broadest dynamic range $ideally, from single atoms to 100% providing the linear relationship between the analyte concentra- content), suppress the matrix effect, eliminate spectral inter- tion and the analytical signal). ferences, minimise the time and cost required for sample prepara- 2. In practice, any sensitivity required for the majority of tion, and pass from multistage to direct methods. Fundamental applications can be provided using commercial instruments, in studies on the development of methods for absolute and stand- particular, ICP-MS $high resolution double-focusing ICP-mass ardless analyses, aimed at avoiding calibration by standards, are spectrometers are used in especially difficult cases). in progress. Ever increasing is the role of the software develop- 3. Atomic absorption, arc and spark emission spectrometers ment, which in certain cases facilitates substantially the deconvo- remain a less expensive alternative to IPC-MS and IPC-AES lution of complex background components, allows digital instruments. Moreover, in practical applications, atomic absorption spectrometers have held the leading position for many decades. Current proliferation of ICP-AES spectrometers A A Bol'shakov, A A Ganeev, V M Nemets St Petersburg State University, approaches that of the former. ul. Ul'yanovskaya 1, 198504 St Petersburg, Russian Federation. Fax $7-812) 428 72 00, tel. $7-812) 428 71 62, e-mail: [email protected] 4. The throughput of analysers has reached a sufficiently high $AABol'shakov), tel. $7-812) 466 41 29, e-mail: [email protected] level, which allows thousands of routine analyses to be performed $AAGaneev), tel. $7-812) 428 44 53 $V M Nemets) daily. The main current tendency is to provide faster and more efficient performance using modern analytical instruments, thus Received 4 April 2005 spending less time and efforts. Uspekhi Khimii 75 $4) 322 ± 338 $2006); translated by T Ya Safonova 5. Further development is aimed at improving sample introduction and simplifying the sample preparation, reducing the total 290 AABol'shakov, AAGaneev, V M Nemets Table 1. Main abbreviations used for particular techniques of analytical atomic spectrometry. Atomic Absorption Atomic Emission Atomic Mass Atomic Fluorescence Atomic Ionisation Spectrometry $AAS) Spectrometry $AES) Spectrometry $MS) Spectrometry $AFS) Spectrometry $AIS) Electrothermal Atomisation Inductively Coupled Inductively Coupled Inductively Coupled Laser-Enhanced Ionisa- AAS $ETA-AAS) Plasma AES $ICP-AES) Plasma MS $ICP-MS) Plasma AFS $ICP-AFS) tion Spectrometry Cavity Ring-Down Laser Ablation ICP-AES Laser Ablation ICP-MS Laser-Excited Atomic Fluo- $LEIS) Spectroscopy $CRDS) $LA-ICP-AES) $LA-ICP-MS) rescence Spectrometry Laser Optogalvanic Intracavity Laser Laser-Induced Breakdown Laser Ablation Mass $LEAFS) Spectrometry $LOGS) Spectroscopy $ICLS) Spectrometry $LIBS) Spectrometry $LA-MS) Resonance Ionisation Mass Spectrometry $RIMS) cost, using new software for the automation of the analysis and element analysis. Studies on the improvement of graphite furna- data processing, making faster analysis and reducing the size of ces, automated introduction of powder and solid samples, flow- the instruments $while the earlier ICP-AES analysers could have injection method and the use of echelle polychromators and the size of a wardrobe, the modern ICP-MS instruments measur- charge-coupled detectors $CCD) for the rapid determination are ing 110660658 cm can be installed on a desk). An active progress in progress. is observed in the development of specialised equipment for the The advantages of continuum spectrum sources $e.g., a power- analysis of specific samples and determination of particular ful xenon short-arc lamp), starting with the possibility of combin- elements. ing simultaneous multielement analysis with simultaneous Annual reviews 1±6 on the analytical atomic spectrometry background correction, were described.24 ± 26 It was shown 27 published by the Journal of Analytical Atomic Spectrometry that the use of the linear photodiode arrays or two-dimensional $London) represent the most convenient literature source to CCD arrays as detectors facilitated reduction of the inaccuracies follow the trends in this field. They summarise new information caused by spatial absorption inhomogeneities in electrothermal on the progress along several directions, including optical and atomisers $ETA). Some of the latest developments, in particular, mass spectral methods, as well as use of spectrometric analysis in use of continuum spectrum sources and cross-dispersed echelle environmental monitoring, industry, biology and medicine. The spectrometers, as well as devices for automatic introduction of total number of citations in these reviews and their distribution powder samples, have already found their application in commer- over different analytical methods reflect the trends of modern cial analysers. studies in atomic spectrometry. The publications cited in these Several summarising papers 28, 29 were devoted to the possibil- reviews may be classified $on the average, over the last 5 years) as ities of the use of diode lasers in AAS. The advantages of broadly follows: modernisation of optical methods Ð 83%, improvement tuneable vertical-cavity surface-emitting laser diodes were illus- in ICP-MS Ð 17%, laser-based methods $including laser ablation trated in Ref. 30 that also cites the original publications on in ICP-MS) Ð 16%. The latter figure illustrates an increased different experimental applications of diode lasers as the sources interest in the development of laser-based methods of analysis of tuneable radiation for determination of absorption by Al, Ba, $publications on routine applications were not considered here). Ca, Cr, Cs, Cu, Gd, Hg, I, In, K, La, Li, Mn, Pb, Rb, Sm, U, Y and The American journal Analytical Chemistry also publishes Zr atoms. However, a much greater number of studies on the use summarising overviews 7, 8 on the atomic spectrometry every two of diode lasers were devoted to the determination of simple years. Aparticularly interesting comparison of different spectro- molecules such as H2O, CO2, CO, NH3, HF, HCl and etc. $see metric methods was carried out on a five-grade scale.9 Several

Load more