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Analytical and Bioanalytical Chemistry (v.359, #6)
Is traceability an exclusive property of analytical results? An extended approach to traceability in chemical analysis by M. Valcárcel; A. Ríos (pp. 473-475).
The need to adapt the definition of traceability in the Metrological Dictionary of ISO to the growing use of this concept in Analytical Chemistry aroused the broader, more flexible proposal expounded in this paper which aims to be closer to the bench level. The traceability concept is addressed in a hierarchical manner by ranking the different notions to which the qualifier “traceable” applies (results, standards, equipment and samples) in such a way that it is compatible with the ISO definition. Relationships among them and with classical analytical properties are also exposed.
Comments to “Is traceability an exclusive property of analytical results? An extended approach to traceability in chemical analysis”M. Valcárcel, A. Ríos, University of Cordoba, Spain Fresenius J Anal Chem (1997) 359 : 473–475
by Y. I. Alexandrov (pp. 476-476).
Development of a fifteen component hydrocarbon gas standard reference material at 5 nmol/mol in nitrogen by G. C. Rhoderick (pp. 477-483).
Primary gravimetric gas cylinder standards containing fifteen alkane, alkene and aromatic hydrocarbons (C2–C10) were prepared. A procedure previously developed to prepare gas cylinder standards for volatile organic compounds at the 5 nmol/mol (ppb) level was used. The set of primary hydrocarbon gas standards prepared by this procedure were intercompared by using gas chromatography with a hydrogen flame ionization detector (GC-FID). The linear regression analysis showed excellent agreement among the standards for each compound. Similar mixtures containing many of these hydrocarbons have been evaluated over time and have shown stability of the concentrations in aluminum gas cylinders for three years. This research resulted in the production and certification of Standard Reference Material (SRM) 1800, which contains fifteen hydrocarbons in nitrogen at a nominal concentration of 5 nmol/mol for each analyte. A batch of twenty-four cylinders containing the mixture was prepared at NIST following previously demonstrated protocols for their preparation. Each cylinder was analyzed against one cylinder from the batch, designated as the “lot control”, for each of the fifteen hydrocarbons. The data showed that the batch was homogeneous, from 0.2 to 0.7% depending on the compound, and stable for each hydrocarbon in the mixture resulting in certification and issuance of SRM 1800.
Determination of antimony species with high-performance liquid chromatography using element specific detection by J. Lintschinger; I. Koch; S. Serves; J. Feldmann; W. R. Cullen (pp. 484-491).
A new method for the fast and simultaneous determination of Sb(III) and Sb(V) is presented involving the use of anion exchange high-performance liquid chromatography (HPLC), a complexing reagent in the mobile phase, and element specific detection with flame atomic absorption spectrometry (FAAS) or inductively coupled plasma mass spectrometry (ICP-MS). Chromatographic parameters such as nature and concentration of the complexing and eluting compounds and pH of the mobile phase were investigated in detail. Additionally, the separation of inorganic Sb(III) and Sb(V) from organically bounded antimony (as (CH3)3SbCl2 and (CH3)3Sb(OH)2) was investigated by using anion, and cation exchange, and reversed phase HPLC. Best separation was obtained with anion exchange HPLC under alkaline conditions. Cation exchange and reversed-phase HPLC were not useful for the separation of the above compounds. With FAAS concentrations in the upper mg L–1 range are detectable, which is not sensitive enough for the analyses of environmental samples. When the chromatographic system was coupled to ICP-MS, the detection limits are in the lower μg L–1 range. The method was applied to various environmental samples with anthropogenic and naturally elevated Sb concentrations.
Determination of trace inorganic selenium in organoselenium (selenosugar) oral nutrition liquids by graphite furnace atomic absorption spectrometry with hydride generation by Zhang De-qiang; Sun Han-wen; Yang Li-li (pp. 492-496).
A method has been proposed for the determination of trace levels of inorganic selenium in organoselenium (selenosugar) oral nutrition liquids using hydride generation-graphite furnace atomic absorption spectrometry (HG-GFAAS), taking advantage of the fact that this organic selenium compound did not generate volatile hydride upon reduction. K2S2O8 was selected for the decomposition of the compound in a boiling water bath. Selenium was found to give a sharp analytical signal upon reduction with NaBH4 in 1.0 mol L-1HCl medium. The characteristic mass giving an integrated absorbance of 0.0044 s was 21 pg. An absolute detection limit (3s) of 36 pg was obtained. The recovery was in the range of 94.2–102.1%. Less than parts per million levels of inorganic Se in the presence of organic selenium can be determined.
Derivatization of aromatic amines for analysis in ammunition wastewater II: Derivatization of methyl anilines by iodination with a Sandmeyer-like reaction by R. Haas; T. C. Schmidt; K. Steinbach; E. von Löw (pp. 497-501).
An analytical method for the determination of aromatic amines in water is introduced that uses iodination with a Sandmeyer-like reaction to replace the amino group by iodine in aqueous solution. The non-polar derivatives are extracted with pentane or toluene, separated with gas chromatography and sensitively detected with an ECD. Thirteen major metabolites of nitroaromatic explosives were investigated. The method was used to analyze these metabolites in water samples from the site of a former ammunition plant. The results are compared with the derivatization of aromatic amines via bromination of the aromatic ring.
Analytical procedure for the analysis of PAHs in biological tissues by gas chromatography coupled to mass spectrometry: application to mussels by P. Baumard; H. Budzinski; P. Garrigues (pp. 502-509).
A rapid, selective and sensitive procedure for the analysis of Polycyclic Aromatic Hydrocarbons (PAHs) in biological organisms has been developed and validated. The freeze-dried tissues were digested in ethanolic KOH. After solvent partitioning, the extract was purified on alumina and silica micro-columns and finally analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The final extract was free of most of the endogenous compounds. A quality assurance/quality control (QA/QC) was carried out. The absolute loss of the target compounds at different stages of the analytical procedure and during all of the procedure was estimated (losses<45%). The recoveries of PAHs were estimated using a certified standard compound solution (recoveries>90%) and spiked mussels (recoveries=100±6%). For validation a certified reference material mussel tissue (recoveries= 90±16%) was analyzed.
Interlaboratory comparison study for the determination of the Fusarium mycotoxins deoxynivalenol in wheat and zearalenone in maize using different methods by R. Schuhmacher; R. Krska; J. Weingaertner; M. Grasserbauer (pp. 510-515).
Seventeen laboratories from six different countries, using their usual in-house methods, participated in an interlaboratory comparison test for the determination of the Fusarium mycotoxins deoxynivalenol (DON) in wheat and zearalenone (ZON) in maize. The toxins generally were extracted from maize and wheat employing mixtures of water, acidified water with an organic solvent or even pure water (for DON). While participants who used enzyme linked immuno sorbent assays (ELISA) for the determination of DON did not perform any clean-up, various techniques were applied for the purification of raw extracts (e.g. liquid/liquid extraction, solid phase extraction (SPE), immuno affinity chromatography (IAC)). For the final separation/quantification step either high performance liquid chromatography (HPLC) (mostly for ZON), gas chromatography (GC) (for DON) or ELISA were employed by participants. The aim of this study was to obtain information about the state of the art of mycotoxin analysis in cereals and to support a knowledge and experience exchange between the participating laboratories in the field of mycotoxin analysis. For each mycotoxin 5 different sample types were distributed, standard solutions (10.10 μg/ml ZON in methanol, 10.09 μg/ml DON in ethyl acetate), blank materials, spiked samples (75.1 μg/kg and 378.3 μg/kg ZON in maize, 126.2 μg/kg and 2519 μg/kg DON in wheat) and naturally contaminated maize and wheat. Coefficients of variation (CV) between laboratory mean results (outliers excluded) ranged from 6.2 to 27.7% for ZON and from 18.9 to 30.0% for DON. Except for the maize samples spiked at 75.1 μg/kg ZON the overall means (outliers rejected) statistically could not be distinguished from the respective target values. Average recoveries of the reported results ranged from 87.7 to 96.2% for ZON and from 94.2 to 108.5% for DON.
Detection of scopolin in the grapefruit (Citrus paradisi Macf.) by Michael Runkel; Anja Moeller; Martin Tegtmeier; Ingo Willigmann; W. Legrum (pp. 516-520).
Ripe fruits of Citrus paradisi Macf. and their juices contain high concentrations of scopolin (β-glucopyranoside of 7-hydroxy-6-methoxycoumarin). The identity of the aglycon being scopoletin was proven analysing extracts of β-glucosidase-treated fruit preparations with TLC, HPLC and GC-MS techniques. The naturally occurring glycoside was identified as the glucoside of scopoletin comparing it with authentic scopolin. The intake of scopolin of either grapefruits or juices thereof leads to a renal excretion of its aglycon as a glucuronide. The excretion is complete within 24 h. An enzymatic hydrolysis of the glucuronide produces scopoletin (i.e. aglycon) which can be quantified by HPLC. Mass spectra revealed that scopoletin releases one methyl- and two carbonyl-groups. The molecule finally breaks into fragments of 51 and 69 atomic mass units.
Characterisation of intermediate layers in hot-dip zinc coated steels
by P. Karduck; T. Wirth; H. Pries (pp. 521-521).