No abstract

The determination of trace elements in pure quartz glass samples has been performed by coupling an ICP quadrupole mass spectrometer with the LINA-Spark-Atomizer, an IR laser ablation system dedicated to direct bulk and surface analysis of solid samples. Linear calibration curves were obtained for nine elements (Na, Al, Ca, Ti, Cr, Mn, Zr, Ba, and Pb) in the ng g(-1) range with detection limits of less than 10 ng g(-1) for Ca, Cr, Mn, Zr, Ba, and Pb and in the range of 120-220 ng g(-1) for Na, Al, and Ti. The distance between the laser focal point and the sample surface has a significant influence on signal intensity and precision, both of which can be improved by a factor of approximately two by focusing the laser 15 mm behind the sample surface. Aerosol moistening reduced the standard deviation of the signal intensity by a factor of 2-4. Signal instability, which resulted from different ablation rates or variations in the transmission of the mass spectrometer, were compensated by use of the simultaneously measured SiAr+ ion as an internal standard. Under these conditions precision was usually better than 5% RSD. The results were compared with those obtained by use of a commercial LA-ICP-MS system. With this instrumentation linear calibration curves were achieved for three elements only (Al, Ti, and Pb), showing that LA-ICP-MS is less appropriate for bulk analysis in the ng g(-1) range.

The original synthesis of glycopyrrolate (NVA237) was revised and shortened into an essentially one-pot process. Without isolating the intermediates, their purification became obsolete, thereby increasing the possibility of the carry over of impurities. For that reason, the actual, potential, and theoretical impurities of the starting materials cyclopentyl mandelic acid and 1-methyl-pyrrolidin-3-ol as well as byproducts which may occur during the synthesis were thoroughly investigated; furthermore, their transformation to possible impurities in the drug substance along the new synthetic route was performed to exclude them as actual impurities in the drug substance with certainty. The question is raised how detailed such investigationwhich are fairly manageable for a simple product like glycopyrrolateneed to be.

Four alternative analytical procedures for the determination of ten important trace impurities (Mg, Cr, Fe, Cu, Zn, Sr, Zr, Cd, Ba, and Pb) in pure alkaline earth fluoride powders were applied using high-resolution inductively coupled plasma mass spectrometry (ICP-MS). Two procedures are based on a wet-chemical microwave digestion with boric acid and quantification by the standard addition technique and isotope dilution mass spectrometry (IDMS), respectively. In addition, analyses are also performed by laser ablation as a direct solid sampling technique applying matrix-matched external calibration as well as isotope dilution of the powdered sample. For most elements good agreement between the different methods is found. Detection limits for laser ablation vary between 0.05 ng g(-1) for Zr and 20 ng g(-1) for Mg. They are about one to two orders of magnitude lower than those of the wet-chemical procedures, which is mainly due to the high dilution factor during the sample preparation step. Advantages and restrictions of the different analytical procedures are discussed with respect to their routine applicability. Due to its relatively high accuracy, low detection limits, and time-efficiency LA-ICP-IDMS is the preferred choice if no standard reference materials are available.

The methods available for determination of environmental contamination by plutonium at ultra-trace levels require labor-consuming sample preparation including matrix removal and plutonium extraction in both nuclear spectroscopy and mass spectrometry. In this work, laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was applied for direct analysis of Pu in soil and sediment samples. Application of a LINA-Spark-Atomizer system (a modified laser ablation system providing high ablation rates) coupled with a sector-field ICP-MS resulted in detection limits as low as 3x10(-13) g g(-1) for Pu isotopes in soil samples containing uranium at a concentration of a few microg g(-1). The isotope dilution (ID) technique was used for quantification, which compensated for matrix effects in LA-ICP-MS. Interferences by UH+ and PbO2+ ions and by the peak tail of 238U+ ions were reduced or separated by use of dry plasma conditions and a mass resolution of 4000, respectively. No other effects affecting measurement accuracy, except sample inhomogeneity, were revealed. Comparison of results obtained for three contaminated soil samples by use of alpha-spectrometry, ICP-MS with sample decomposition, and LA-ICP-IDMS showed, in general, satisfactory agreement of the different methods. The specific activity of (239+240)Pu (9.8 +/- 3.0 mBq g(-1)) calculated from LA-ICP-IDMS analysis of SRM NIST 4357 coincided well with the certified value of 10.4 +/- 0.2 mBq g(-1). However, the precision of LA-ICP-MS for determination of plutonium in inhomogeneous samples, i.e. if "hot" particles are present, is limited. As far as we are aware this paper reports the lowest detection limits and element concentrations yet measured in direct LA-ICP-MS analysis of environmental samples.