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Author Lindner, H.; Murtazin, A.; Groh, S.; Niemax, K.; Bogaerts, A. pdf  doi
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  Title Simulation and experimental studies on plasma temperature, flow velocity, and injector diameter effects for an inductively coupled plasma Type A1 Journal article
  Year (down) 2011 Publication Analytical chemistry Abbreviated Journal Anal Chem  
  Volume 83 Issue 24 Pages 9260-9266  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract An inductively coupled plasma (ICP) is analyzed by means of experiments and numerical simulation. Important plasma properties are analyzed, namely, the effective temperature inside the central channel and the mean flow velocity inside the plasma. Furthermore, the effect of torches with different injector diameters is studied by the model. The temperature inside the central channel is determined from the end-on collected line-to-background ratio in dependence of the injector gas flow rates. Within the limits of 3% deviation, the results of the simulation and the experiments are in good agreement in the range of flow rates relevant for the analysis of relatively large droplets, i.e., 50 μm. The deviation increases for higher gas flow rates but stays below 6% for all flow rates studied. The velocity of the gas inside the coil region was determined by side-on analyte emission measurements with single monodisperse droplet introduction and by the analysis of the injector gas path lines in the simulation. In the downstream region significantly higher velocities were found than in the upstream region in both the simulation and the experiment. The quantitative values show good agreement in the downstream region. In the upstream region, deviations were found in the absolute values which can be attributed to the flow conditions in that region and because the methods used for velocity determination are not fully consistent. Eddy structures are found in the simulated flow lines. These affect strongly the way taken by the path lines of the injector gas and they can explain the very long analytical signals found in the experiments at low flow rates. Simulations were performed for different injector diameters in order to find conditions where good analyte transport and optimum signals can be expected. The results clearly show the existence of a transition flow rate which marks the lower limit for effective analyte transport conditions through the plasma. A rule-of-thumb equation was extracted from the results from which the transition flow rate can be estimated for different injector diameters and different injector gas compositions.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Washington, D.C. Editor  
  Language Wos 000297946900013 Publication Date 2011-07-29  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 6.32 Times cited 34 Open Access  
  Notes Approved Most recent IF: 6.32; 2011 IF: 5.856  
  Call Number UA @ lucian @ c:irua:94001 Serial 3009  
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Author Lindner, H.; Loper, K.H.; Hahn, D.W.; Niemax, K. doi  openurl
  Title The influence of laser-particle interaction in laser induced breakdown spectroscopy and laser ablation inductively coupled plasma spectrometry Type A1 Journal article
  Year (down) 2011 Publication Spectrochimica acta: part B : atomic spectroscopy Abbreviated Journal Spectrochim Acta B  
  Volume 66 Issue 2 Pages 179-185  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract Particles produced by previous laser shots may have significant influence on the analytical signal in laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma (LA-ICP) spectrometry if they remain close to the position of laser sampling. The effects of these particles on the laser-induced breakdown event are demonstrated in several ways. LIBS-experiments were conducted in an ablation cell at atmospheric conditions in argon or air applying a dual-pulse arrangement with orthogonal pre-pulse, i.e., plasma breakdown in a gas generated by a focussed laser beam parallel and close to the sample surface followed by a delayed crossing laser pulse in orthogonal direction which actually ablates material from the sample and produces the LIBS plasma. The optical emission of the LIBS plasma as well as the absorption of the pre-pulse laser was measured. In the presence of particles in the focus of the pre-pulse laser, the plasma breakdown is affected and more energy of the pre-pulse laser is absorbed than without particles. As a result, the analyte line emission from the LIBS plasma of the second laser is enhanced. It is assumed that the enhancement is not only due to an increase of mass ablated by the second laser but also to better atomization and excitation conditions favored by a reduced gas density in the pre-pulse plasma. Higher laser pulse frequencies increase the probability of particle-laser interaction and, therefore, reduce the shot-to-shot line intensity variation as compared to lower particle loadings in the cell. Additional experiments using an aerosol chamber were performed to further quantify the laser absorption by the plasma in dependence on time both with and without the presence of particles. The overall implication of laser-particle interactions for LIBS and LA-ICP-MS/OES are discussed.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Oxford Editor  
  Language Wos 000289328900012 Publication Date 2011-01-20  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0584-8547; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.241 Times cited 12 Open Access  
  Notes Approved Most recent IF: 3.241; 2011 IF: 2.876  
  Call Number UA @ lucian @ c:irua:89008 Serial 1627  
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Author Lindner, H.; Autrique, D.; Garcia, C.C.; Niemax, K.; Bogaerts, A. doi  openurl
  Title Optimized transport setup for high repetition rate pulse-separated analysis in laser ablation-inductively coupled plasma mass spectrometry Type A1 Journal article
  Year (down) 2009 Publication Analytical chemistry Abbreviated Journal Anal Chem  
  Volume 81 Issue 11 Pages 4241-4248  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract An optimized laser ablation setup, proposed for high repetition rate inductively coupled plasma mass spectrometry (ICPMS) analyses such as 2D imaging or depth profiling, is presented. For such applications, the particle washout time needs to be as short as possible to allow high laser pulse frequencies for reduced analysis time. Therefore, it is desirable to have an ablation setup that operates as a laminar flow reactor (LFR). A top-down strategy was applied that resulted in the present design. In the first step, a previously applied ablation setup was analyzed on the basis of computational fluid dynamics (CFD) results presented by D. Autrique et al. (Spectrochim. Acta, B 2008, 63, 257−270). By means of CFD simulations, the design was modified in such a way that it operated in the LFR regime. Experimental results demonstrate that the current design can indeed be regarded as an LFR. Furthermore, the operation under LFR conditions allowed some insight into the initial radial concentration distribution if the experimental ICPMS signal and analytical expressions are taken into account. Recommendations for a modified setup for more resilient spatial distributions are given. With the present setup, a washout time of 140 ms has been achieved for a 3% signal area criterion. Therefore, 7 Hz repetition rates can be applied with the present setup. Using elementary formulas of the analytical model, an upper bound for the washout times for similar setups can be predicted. The authors believe that the presented setup geometry comes close to the achievable limit for reliable short washout times.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Washington, D.C. Editor  
  Language Wos 000266601800014 Publication Date 2009-04-29  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 6.32 Times cited 18 Open Access  
  Notes Approved Most recent IF: 6.32; 2009 IF: 5.214  
  Call Number UA @ lucian @ c:irua:76935 Serial 2492  
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Author Autrique, D.; Bogaerts, A.; Lindner, H.; Garcia, C.C.; Niemax, K. doi  openurl
  Title Design analysis of a laser ablation cell for inductively coupled plasma mass spectrometry by numerical simulation Type A1 Journal article
  Year (down) 2008 Publication Spectrochimica acta: part B : atomic spectroscopy Abbreviated Journal Spectrochim Acta B  
  Volume 63 Issue 2 Pages 257-270  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Oxford Editor  
  Language Wos 000254038900016 Publication Date 2007-12-05  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0584-8547; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.241 Times cited 26 Open Access  
  Notes Approved Most recent IF: 3.241; 2008 IF: 2.853  
  Call Number UA @ lucian @ c:irua:67086 Serial 656  
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