Reduction of polyatomic ion interferences in inductively coupled plasma mass spectrometry by cryogenic desolvation (original) (raw)
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EFFECT OF THE MATRIX IN MASS SPECTROMETRY USING AN INDUCTIVELY COUPLED PLASMA
Using different types of devices, we have performed an experimental study of matrix ionization effects manifesting themselves in the method of mass spectrometry with an inductively coupled plasma. Basic laws governing these effects have been established. The composition of the analytical zone of the plasma and possible attenuation of the signal from the analyte on introduction of a matrix element due to processes occurring in the plasma and in the ion beam have been determined theoretically. A high degree of coincidence between experimental and calculated results is shown.
Spectrochimica Acta Part B: Atomic Spectroscopy, 1999
The Common Analyte Internal Standardization CAIS chemometric technique is extended to correct for Ž. non-spectroscopic matrix effects in inductively coupled plasma-mass spectrometry ICP-MS. The approach is based on using an internal reference element to correct for the matrix effect. Unlike the conventional internal reference method, the CAIS technique allows for the analyte to behave differently from the internal reference under the influence of the matrix. With the CAIS technique a single internal reference element is sufficient to correct for all the analytes. Experimental tests with 13 analytes in four different matrices using different ICP-MS instruments demonstrate that the CAIS is efficient and general for matrix effect correction. Not only is the corrected concentration more accurate, but the precision is significantly better. The capability of CAIS to correct for the effect of a mixture of two matrices was also established experimentally, and 20᎐30% matrix suppression was eliminated. Furthermore, the developed technique was used as a simple diagnostic quality assurance procedure to evaluate the performance of the mass spectrometer.
Matrix effects in secondary ion mass spectrometry
Analytical Chemistry, 1983
An ammonium chloride matrlx used In secondary ion mass spectrometry of organlc salts leads to enhanced signals due to the Intact ion and to decreased fragmentation. Slmllar results are reported with the use of other solid and liquid matrices, but ammonlum chlorlde Is advantageous In that it does not contribute to the spectral background. As a result, data can be obtained from very dilute mixtures, and analyses of organlc salts at the Row parts-permillion level in ammonium chlorlde are presented. The results are Lnterpreted to suggest mechanisms In which large clusters of Ions and molecules are sputtered from the surface, with subsequent dlssociatlon leading to Intact anaiyte Ions. Large scale mixlng of molecules accompanles energetic Ion beam bombardment. Ions from nonvolatile, thermally fragile, and high molecular weight compounds are created by the techniques of desorption ionization mass spectrometry (I). Particular methods include secondary ion mass spectrometry (SIMS) (2), fast atom bombardment (FAB) (3), laser desorption (LD) (4), and fission fragment or plasma desorption (PD) (5). Energetic ions, atoms, photons, and nuclear fission fragments produce similar spectra (6). These contain ions which indicate molecular weight (e.g., (M + H)+, (M + Na)+, and (M-H)-, or C+ and
Spectrochimica Acta Part B: Atomic Spectroscopy, 1987
Reported are the effects of easily ionizable concomitant elements on non-spectroscopic interferences in ' ICP-MS. Analyte ion suppression was studied for Lt.. " B '*Ni "%c "Y and "OsTI in the presence of concomitant , , , elements spanning a mass range from 23 (Na) to 207 (Pb) daltons. For the analytes studied, it was found that the greater the atomic mass of the concomitant element, the greater was the analyte ion count rate suppression. For a given set of experimental conditions, the greater the atomic mass of the analyte, the lower was its susceptibility to ion count rate suppression by any concomitant element. The severity of non-spectroscopic interferences decreased as the sampler orifice was positioned further away from the center of the plasma and also as the sampling depth was increased. Dilution of a solution containing a given molar ratio of concomitant to analyte reduced the extent of analyte ion suppression. Non-spectroscopic interferences in ICP-MS can be attributed to ambipolar diffusion effects in the plasma that result from the presence of easily ionizable concomitant elements.
The effect of pre-evaporation on ion distributions in inductively coupled plasma mass spectrometry
Spectrochimica Acta Part B: Atomic Spectroscopy, 2006
The connecting tube (2 or 5-mm i. d., 11-cm long) between the spray chamber and the torch was heated (to 400 -C) to investigate the effect of pre-evaporation on the distribution of ions in inductively coupled plasma mass spectrometry (ICP-MS). Axial and radial profiles of analyte ions ) in 1% HNO 3 as well as some polyatomic ions (LaO + , ArO + , ArN + , CO 2 + ) were simultaneously obtained on a time-of-flight ICP-MS instrument. Upon heating the connecting tube, the optimal axial position of all elements shifted closer to the load coil. Without the heated tube, 3.5 mm was the compromise axial position for multielemental analysis, which was optimal for 6 analytes. With the heated tube, this position became 1.5 mm, which was then optimal for 9 of the 14 analytes. Furthermore, the radial profiles, which were wide with a plateau in their middle without heating, became significantly narrower and Gaussian-like with a heated tube. This narrowing, which was most important for the 5-mm tube, slightly (by a factor of two at the most) yet significantly (at the 95% confidence level) improved the sensitivity of all elements but Mn upon optimisation of the axial position for compromise multi-element analysis. Furthermore, a concurrent decrease in the standard deviation of the blank was significant at the 95% confidence level for 9 of the 14 analytes. For most of the analytes, this translated into a two-fold to up to an order of magnitude improvement in detection limit, which is commensurate with a reduction of noise resulting from the smaller droplets entering the plasma after traversing the pre-evaporation tube.
Prediction of Multiple Matrix Interferences in Inductively Coupled Plasma Mass Spectrometry
Applied Spectroscopy, 2001
Matrix effects for pairs of interferents (Al, Na, K, Ba, and Cs) were investigated and compared to predictions of the amount of interference determined by single interferent experiments in order to test a model called the total interference level (TIL), which assumes that the effects of different interferents add linearly. The TIL model is part of an Autonomous Instrument and is designed to indicate when a simple default calibration, such as external calibration or internal standardization, is inadequate for the desired accuracy of analysis. The performance of the TIL model was examined in terms of a daily calibration basis, which should be more accurate, and an occasional calibration basis, which is more convenient, considering simple external standardization and internal standardization as the techniques to be tested for desired accuracy. The results are encouraging for multiple interferences and show that the TIL model can serve a useful function in predicting calibration errors,...