Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' journal of analytical chemistry 359 (1997), S. 414-417 
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The detection limit of ICP-MS is affected by the sensitivity, the height of the blank and its relative stability i.e. precision, the accuracy and additionally by a bias or systematical error. The improvement of a single factor will improve the efficiency of the whole analytical system. For the example of uranium determination in process chemicals such as concentrated HF and HNO3 the improvement or deterioration of the factors given above is demonstrated. The applied methods are matrix removal by evaporation, highly efficient nebulization with a USN, isotope dilution and use of a double-focusing instrument (ICP-SFMSLR). The increase or decrease of each factor is compared to conventional nebulization ICP-QMS. To take full advantage of each single method, they can be combined with each other. Possible drawbacks of a single method are compensated by another method. Detection limits for uranium in concentrated process chemicals in the sub-pg/g range can be achieved.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' journal of analytical chemistry 360 (1998), S. 800-803 
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract For fast routine analysis of process chemicals used in semiconductor technology such as tetramethylammonium hydroxide (TMAH), ammonium fluoride/hydrofluoric acid mixtures, phosphoric, sulphuric or peroxodisulphuric acid (PDSA) low blanks are the paramount requirement for reliable sector field ICP-MS ultratrace analysis. When solutions containing a high amount of dissolved solids e.g. seawater samples have been analysed before, a thorough cleaning procedure and an adapted element menu is essential to lower the instrument blanks where possible or to achieve sufficient limits of detection (LoD) even at high blank levels. Due to its improved transmission and its ability to resolve spectral interferences inductively coupled plasma-sector field mass spectrometry is capable of detecting 1 ng/g of all metal impurities even K, Ca, and Fe in every matrix used for semiconductor production. LoDs range from 〈 1 to 30 pg/mL in diluted chemicals corresponding to 5 to 800 pg/mL in the original. This work describes the experiences with instrument cleaning and maintenance, sample preparation and introduction. The interface region between torch and lenses was seen to be the main source of blanks for elements such as Na. All sample manipulation has to be carried out under clean room conditions. The use of an inert sample introduction system (ISIS), platinum cones and at least medium resolution for elements between 24 and 80 amu creates a very robust method. High efficiency sample introduction systems such as USN and MCN have been studied alternatively.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' journal of analytical chemistry 360 (1998), S. 520-526 
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A thermal trace-matrix separation procedure has been developed for the determination of ultra-traces of metals in solid non-metals (P, As, Sb, S, Se, Te and I). These matrices are dissolved in high-purity hydrogen peroxide to form the corresponding acids. By applying a suitable temperature profile, coating the graphite tube with WC and using hydrogen as a gaseous modifier more than 90% of the matrix can be removed. Analyte recoveries are 90 to 105% with a standard deviation of 5 to 10%. Since the separation principle is not specific, non-metallic analytes show poor recoveries of 10 to 40% (20–100% RSD). Elements forming persistent carbides, such as refractory metals, require either HF or freon as an additional modifier. Separation of the matrix leads to higher sensitivities, fewer spectral and non-spectral interferences and to better precision. The graphite tube is only little contaminated and its lifetime is drastically increased. The improvements result in limits of detection in the lower pg/g-range in the solid non-metals. Furthermore, this method can be employed for amounts of sample around 1 mg at absolute detection limits below 1 pg. Best performance of the coupling of ETV to ICP-MS is only obtained in the single-ion monitoring mode which means only semi-sequential multi-element capabilities.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 336 (1994), S. 408-414 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ultratrace Analysis in High Purity Phosphorus by Thermal Trace-matrix-separation via ETV-ICP-MSElemental (red) phosphorus can be effectively volatilized and separated from ultra trace contaminants by electrothermal vaporization (ETV) in a graphite furnace. The tube must be covered with WC and some hydrogen added to the transport argon. Detection limits of 0,01 to 10 ng/g in the phosphorus sample are obtained for most analytes by ICP-MS in single ion monitoring mode. Exceptions are some carbide forming elements (B, Si, V), some contaminants from the graphite (B, Si) and some easily volatile traces (As, Sb, Te, I). ETV in multi element scan mode or alternatively wet chemical trace matrix separation (SMT) with an cation exchanger plus nebulizer aspiration allow detection limits about one order higher. The proposed technique requires a minimum of chemical manipulation and therefore reduces risk of contamination.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 179 (1961), S. 70-71 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 354 (1996), S. 807-810 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract If sample pretreatment, nebulization and method of calibration are suitably adapted to each other the performance of inductively coupled plasma – mass spectrometry ICP-MS can be greatly increased. High accuracy is obtained by high precision and low bias. For a given concentration higher sensitivity means higher count rates and therefore higher precision. Systematic errors are minimized by employing a definitive method of calibration. Increased sensitivity is obtained by introducing higher amounts of sample into the measurement system via high efficiency nebulizers (ultrasonic nebulizer, hydraulic-high pressure nebulizer according to Berndt and concentric high efficiency nebulizer according to Meinhard). Because this means also higher matrix effects a combination of ion chromatographic (IC-TMS) and thermal trace-matrix-separation by aerosol desolvation (T-TMS) is introduced. Isotope dilution (ID) proves to be the calibration most suitable to achieve the highest accuracy. First applications on the analysis of refractory metals (e.g. Ti, V, Nb, Ta) and non-metals (e.g. P, S, As, Se) showed recoveries of 60–105%, an imprecision of the recoveries of 2–50%, but an overall inaccuracy of only 0.1 to 4%.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 337 (1995), S. 542-547 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Comparison of Nebulizer Efficiencies with Thermal Trace-Matrix-Separation for the Analysis of Corrosive Samples by ICP-MS on the Semi-Micro-ScaleNew, highly efficient aerosole generating techniques such as ultrasonic nebulization (USN), hydraulic high pressure nebulization (HHPN) and Meinhard high efficiency nebulization (HEN) are adapted for the on-line analysis of corrosive samples by ICP-MS. Nebulization efficiencies range from 10 to 60%. A desolvation and condensation assembly is described. It allows on-line thermal trace-matrix separation and ensures reduction of all major acid components (HF, HCl, HNO3,H2SO4, H3PO4) and of methanol by 90 to 98%. Non-metals (B, Si, Se, Br, I) are washed out and could not be analyzed in the ng/g range. For 68 other analytes recoveries are 95%. The analyte-matrix ratio is increased by a factor of 5 to 25 and detection limits improved by a factor of 2 to 20. Most polyatomic interferences are reduced. Using this system, HPLC, IC, and other trace-matrix separation techniques developed for ICP-AES can, in many cases, be directly applied to ICP-MS. The selective condensation of acids avoids evaporation and its risk of contamination. The entire assembly fits into the torch box of the VG Plamaquad 2+. The system requires sample volumes of less than 1 mL, which allows applications of semi-micro techniques. The total improvement of the detection limits amounts to a factor of 5 to 100 in the ng-range. All results are compared to standard nebulizers and FIA.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 339 (1997), S. 107-113 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Approaches to the Quantification of the Robustness as a Figure of Merit for Analytical Systems with Regard to Validation and ComparabilityRobustness and susceptibility have been introduced to characterize the effects of small variations of the system variables V on the performance S of an (analytical) system in the vicinity of a given working point. To describe the performance over the entire possible range of the parameter variations integral robustness Rint, roughness LR and total robustness Rges are defined as additional descriptors. Normalization of all scales to the interval 0 to 1 and appropriate definition of R and L lead to dimensionless data. These figures of merit allow to compare the effects of very different variables or of the performance of different procedures. The characterization of the system by Rint, LR and Rges requires the (approximate) knowledge of the functional dependence S=f(V) of the system on the respective variable. This function may be obtained from models or from (factorial) experimentation. Examples are given for the validation and comparison of ICP-MS, ICP-AES and AAS.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...