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1.
Jürgen Reiß 《Fresenius' Journal of Analytical Chemistry》1978,293(2):138-140
Summary Spots of citrinin, ochratoxin A, aflatoxin M1 and penicillic acid on thin-layer chromatograms can be semi-quantitatively estimated by using a grey scale, commonly used in photo laboratories. The detection limits are 0.01 g for citrinin, 0.006 g for ochratoxin A, 0.002 g for aflatoxin M1 and 0.01 g for penicillic acid. Standard curves for these mycotoxins are given.
Halbquantitative Bestimmung der Mycotoxine Citrinin, Ochratoxin A, Aflatoxin M1 und Penicillinsäure auf Dünnschicht-Chromatogrammen mit Hilfe eines Graukeils
Zusammenfassung Mit Hilfe eines in Photolabors gebräuchlichen Graukeils können dünnschicht-chromatographische Flecke der obengenannten Mycotoxine halbquantitativ bestimmt werden. Die Nachweisgrenzen betragen 0,01 g für Citrinin, 0,006 g für Ochratoxin A, 0,002 g für Aflatoxin M1 und 0,01 g für Penicillinsäure. Eichkurven werden angegeben.相似文献
2.
Summary The quantitative determination of trace elements in human blood serum by Total Reflection X-Ray Fluorescence Analysis (TXRF) is influenced by absorption- and reflection-effects caused by the organic (proteins) and inorganic (P, S, Na, K, Ca, Cl) matrices. To minimize these effects we have developed a sample preparation technique based on the decomposition of the organic matrix and followed by the separation of the trace elements from the organic matrix by ion-exchange. The described method enables the simultaneous determination of K (1584 g), Ca (666 g), Fe (22 g), Cu (9.6 g), Zn (8.8 g), Se (0.97 g), Sn (1.3 g), Pb (0.12 g) and Rb (1.6 g) (obtained values in parentheses).
Herrn Prof. Dr. G. Tölg zum 60. Geburtstag gewidmet 相似文献
Herrn Prof. Dr. G. Tölg zum 60. Geburtstag gewidmet 相似文献
3.
L. Nitschke R. Müller G. Metzner L. Huber 《Fresenius' Journal of Analytical Chemistry》1992,342(9):711-713
Summary A simple and fast determination of trace amounts of commercially used cationic surfactants is described. After extraction from water cationic surfactants are separated by HPLC and detected by conductometry. The detection limit is 3 g/l for distearyldimethylammonium chloride, 16 g/l for ditallowimidazolinium methosulphate, and 6 g/l for dodecylpyridinium chloride. 相似文献
4.
Zusammenfassung Eine quantitative Spurenbestimmung von Europium in Gadolinium, Praseodym in Neodym und Lutetium in Ytterbium konnte durch Aktivierung der Proben und nachfolgende Abtrennung am Kationenaustauscher Dowex 50W×8 ausgearbeitet werden. Eine vollständige Trennung von Europium und Gadolinium sowie Praseodym und Neodym konnte mit wäßrigen Ammonium--hydroxyisobutyrat-Lösungen erreicht werden. Für die Trennung von Ytterbium und Lutetium erwies sich Ammoniumlactat als geeigneter. Die Position der Elutionspeaks war in jedem Fall einwandfrei reproduzierbar.Mit Hilfe dieses Verfahrens bestimmten sich die Restverunreinigungen in den verwendeten Präparaten zu 0,065 g EuO1,5/mg GdO1,5; 1,2 g PrO1,83/mg NdO1,5 und 1,5 g LuO1,5/mg YbO1,5.
A quantitative determination of Eu in Gd, Pr in Nd, and Lu in Yb has been performed by activation of the samples followed by separation on cation exchanger Dowex 50W×8. Complete separation in the systems Eu-Gd and Pr-Nd was achieved with aqueous ammonium -hydroxyisobutyrate solutions, ammonium lactate giving better results in the case of Yb and Lu. In all cases the reproducibility of the position of the elution peaks was satisfactory.Using this separation technique the residual impurities in the given samples were estimated to 0,065 g EuO1,5/mg GdO1,5; 1,2 g PrO1,83/mg NdO1,5, and 1,5 g LuO1,5/mg YbO1,5 respectively.相似文献
5.
U. M. Kasar A. R. Joshi S. K. Patil 《Journal of Radioanalytical and Nuclear Chemistry》1984,81(1):109-115
Fluoride and sulphate complexing of Np(VI) has been studied by controlled-potential coulometry at a constant ionic strength. The values of
1
*
and
2
*
for fluoride complexes were found to be 9.4 and 8.9, respectively, at an ionic strength =0.5. At an ionic strength =1.0,
1
*
and
2
*
obtained were 6.6 and 10.5, respectively. Sulphate complexing of Np(VI) was studied only at an ionic strength =0.5. The value of
1
*
obtained was 5.6. 相似文献
6.
Xu Feng Sun Wen-Hua Yang Shi-Yan Yin Yan-Qi Wu Qin-Jin Yu Kai-Bei 《Transition Metal Chemistry》1997,22(2):176-179
HFe2Co(CO)9(3-S) reacts with (5-Cp)Mo(CO)3Cl in refluxing THF to give heterometallic trinuclear clusters (5-Cp)MoFeCo(CO)8(3-S) and [(5-Cp)Mo]2Fe(CO)7-(3-S), which have been characterized by elemental analyses, i.r., 1H- and 13C-n.m.r. and X-ray crystal structure determination. An electrophilic addition–elimination sequence is proposed for their formation. 相似文献
7.
Zusammenfassung Eine neue Methode zur Durchführung gravimetrischer Bestimmungen im Mikrogrammbereich wurde beschrieben; diese beruht im wesentlichen darauf, daß der Niederschlag nicht mehr zusammen mit dem Filter, sondern nach Überführen mit einem geeigneten Lösungsmittel in einem separaten Wägegefäß gewogen wird.Die dazu nötigen Geräte und deren Herstellung wurden beschrieben. Nach dieser Methode wurden folgende Bestimmungen mit zufriedenstellender Richtigkeit durchgeführt: 2,5–25g Al, 5–50g Cu und 5–50g Zn mit Oxin, 2,5–25g Fe(III) und 2,5–25g Ti(IV) mit N-Benzoyl-phenylhydroxylamin, 5–50g Ni und 5–50g Cu mit Salicylaldoxim, 2,5–50g Co(II) und 2,5–50g Fe(III) mit -Nitroso--naphthol sowie 5–50g Chlorid als Silberchlorid.
Precipitation analysis in the microgram-scale: A new method
Summary A new method for gravimetric determinations in the microgram-scale is described. This method is based on the fact that the precipitate is not weighed together with the filter but is transferred to a separate weighingvessel using a suitable solvent. The necessary simple devices and their use are described. The following determinations were carried out with satisfying accuracy: 2,5–25g Al, 5–50g Cu and 5–50g Zn with Oxine, 2,5–25g Fe and 2,5–25g Ti withN-benzoylphenylhydroxylamine, 5–50g Ni and 5–50g Cu with salicylaldoxime, 2,52–50g Co and 2,5–50g Fe with -nitroso--naphthol and 5–50g chloride as silver chloride.相似文献
8.
Zusammenfassung Ein schnelles und einfaches Mikroverfahren zum Nachweis einiger Heteroatome organischer Verbindungen wurde entwickelt. Nach Aufschluß mit metallischem Kalium werden die entstehenden Ionen mit der Ringofenmethode getrennt und mit empfindlichen Reaktionen nachgewiesen. Nachweisgrenze: 0,5 bis 1g Stickstoff, 1 bis 2g Schwefel, 2 bis 3g Jod, 4 bis 5g Brom, 5 bis 10g Chlor in 0,5 bis 1 mg Einwaage.
Summary A rapid and simple micromethod was developed for the detection of several hetero-elements in organic compounds. After breaking down the sample with metallic potassium, the resulting ions are separated by the ring oven method and detected by means of sensitive reagents. Detection limits: 0.5 to 1g nitrogen, 1 to 2g sulfur, 2 to 3g iodine, 4 to 5g bromine, 5 to 10g chlorine in samples weighing 0.5 to 1 mg.
Résumé On a découvert un procédé à l'échelle micro, simple et rapide, pour rechercher certains hétéroéléments dans les composés organiques. Après mise en solution par le potassium métallique, on sépare les ions formés suivant la méthode du four annulaire et l'on effectue la recherche au moyen de réactions sensibles. Limite de dilution: 0,5 à 1g d'azote, 1 àg de soufre, 2 àg d'iode, 5 à 10g de chlore sur 0,5 à 1 mg de prise d'essai.相似文献
9.
S. Alexandropoulos A. Tsatsaronis P. Haimalas Ch. Kordulis 《Reaction Kinetics and Catalysis Letters》1991,43(2):329-333
The effects of calcination temperature on structural and textural characteristics of two Greek bauxites were examined by different physicochemical techniques. Although the above minerals exhibited lower activity than a commercial CoMo/Al2O3 catalyst, they were evaluated as possible hydrotreating catalysts.
. , CoMo/Al2O3, , .相似文献
10.
The new cubane cluster complex K6[Ta4(4-O)(3-Te)4(CN)12]·KOH·4H2O was prepared from a mixture of TaTe4 and KCN by the high-temperature synthesis followed by crystallization from aqueous solutions. The compound was characterized by cyclic voltammetry, X-ray diffraction analysis, and IR, Raman, and electronic spectroscopy. A comparative study of the clusters [M4(4-O)(3-Te)(CN)12]6– (M = Nb or Ta) containing the 4-O ligands was carried out. These clusters are the first molecular chalcogenide cubane complexes of Group V metals. 相似文献
11.
J. R. Castillo J. M. Mir C. Martinez M. T. Gomez 《Fresenius' Journal of Analytical Chemistry》1986,325(2):171-174
Summary Optimum for the generation of arsine from As(III) and (V) in a generating system without carrier gas and with atomization in an air-acetylene flame were established. A 3% solution of NaBH4 was used as reducer. The effect of 26 different species on the determination of arsenic was studied. The method has been applied to determine arsenic in copper.A linear relationship exists between 0.5 and 3 g for As(III) and between 1 and 4 total g of As(V). The sensitivity, expressed as the slope of the calibration curve is 0.067 g–1 for As(III) and 0.054 g–1 for As(V); the characteristic masses are 1.22 g and 0.44 g, and the limits of detection 0.27 g and 0.33 g, respectively.
This work has been sponsored by the CAICYT (project 3378/83) of the Spanish Education and Science Department. 相似文献
Direkte Flammen-AAS — Erzeugung flüchtiger kovalenter HydrideStörungen durch das Verhältnis der As(III/V)-Valenzstufen und Arsenbestimmung in Kupfer
Zusammenfassung Optimale Bedingungen wurden ausgearbeitet für die Arsinerzeugung aus As(III) und As(V) in einem System ohne Trägergas mit Atomisierung in einer Luft-Acetylen-Flamme. Zur Reduktion dient eine 3%ige NaBH4-Lösung. Der Einfluß von 26 Fremdionen wurde geprüft und das Verfahren zur Arsenbestimmung in Kupfer angewendet. Eine lineare Beziehung ergab sich für 0,5–3 g As(III) und 1–4 g As(V). Die Empfindlichkeit (als Neigung der Eichkurve) beträgt 0,067 g–1 für As(III) und 0,054 g–1 für As(V). Die charakteristischen Massen sind 1,22 g bzw. 0,44 g und die Nachweisgrenzen 0,27 g bzw. 0,33 g.
This work has been sponsored by the CAICYT (project 3378/83) of the Spanish Education and Science Department. 相似文献
12.
V. Ragaini M. Navarra A. Spadaro N. Giordano 《Reaction Kinetics and Catalysis Letters》1975,2(1-2):19-27
The dehydrogenation and hydrogenolysis of n-butane (n-C4) over a Ru–Al2O3 catalyst (0.849 w/w% Ru) have been studied at 490°C at different time factors. Some runs have also been made on pure -Al2O3 at 490°C and on Ru-black at temperatures between 100 and 490°C, feeding n-butane and hydrogen. The analysis of the selectivity vs. time factor allows to prove that the initial reactions taking place are n-C4 dehydrogenation to 1-butene and 2-butenes and skeletal isomerization to isobutane. The initial molar selectivity to the n-butenes reaches about 70%. A qualitative reaction scheme is proposed.
- (-C4) Ru–Al2O3 (0,849 .% Ru) 490°C . -Al2O3 490°C Ru- 100–490°C - . , -C4 1- 2- . - 80%. .相似文献
13.
Furusawa N 《Analytical and bioanalytical chemistry》2004,378(8):2004-2007
A method for the determination of aldrin, dieldrin, DDT, DDE, and DDD contamination in animal fats (beef tallow, lard, and chicken fat) without using toxic reagents is developed, that uses high-performance liquid chromatography after the sample has been prepared by matrix solid-phase dispersion (MSPD) with acidic alumina oxide. A reversed-phase C1-silica column with a mobile phase of 50% (v/v) ethanol solution (in water) and a photo-diode array detector were used for the determination. Average recoveries of the target compounds (0.2–5.0 g g–1) ranged from 84–98%, with coefficients of variation of <5%. The limits of quantitation were 0.16 g g–1 for AD, 0.10 g g–1 for DD, 0.06 g g–1 for DDT, 0.07 g g–1 for DDE, and 0.05 g g–1 for DDD. No toxic reagents were used at all. 相似文献
14.
M. Vobecký 《Journal of Radioanalytical and Nuclear Chemistry》1989,135(3):171-176
The interference contributions of uranium and thorium to the determination of cerium based on radionuclides141Ce and143Ce produced by irradiation in a reactor core was determined. The values of the interference contributions for141Ce were 0.28±0.01 g Ce/g U and /2.01±0.05/x10–3 g Ce/g Th, and for143Ce 1.33±0.03 g Ce/g U and /9.0±0.2/x10–3 g Ce/g Th. 相似文献
15.
C. M. Sunta H. S. Dang D. D. Jaiswal 《Journal of Radioanalytical and Nuclear Chemistry》1987,115(1):149-158
The intake and tissue distribution of thorium (2 3 2Th) was studied in an urban (Bombay) population in India. From the analysis of 16 whole diet samples, the average daily intake through food was found to be 2 g (range 0.8–4.3 g·d–1). The estimated intake through drinking water and inhalation comes out to be 0.03 and 0.02 g per day. From the analysis of human autopsy tissue samples it is observed that the concentration ranges in lungs and bone are 1.5–16 g/kg and 0.2–9.0 g/kg fresh weight respectively. The average urinary concentration is 12 ng/1 (range 7–22 ng/l for 10 samples). Among the different body tissues, pulmonary lymph nodes were found to contain the highest concentration (geometric mean 53.4 g/kg, range 31.4–85.5 g/kg for 6 samples). Analysis of the samples was done by the neutron activation technique. 311.8 keV gamma photons of2 3 3Pa which is the activation product of2 3 2Th, were counted after chemical separation. A 54 cm3 intrinsic Ge detector coupled to 1024-channel analyser was used. Using the average lung content and the daily average intake values of thorium through inhalation, the clearance half-time from lung was estimated. 相似文献
16.
A. B. Melent'ev 《Journal of Analytical Chemistry》2004,59(10):972-975
A procedure was developed for the gas-chromatographic determination of promedol (trimeperidine) and ketamine in whole blood with mass-selective detection. The detection limit for trimeperidine and ketamine in blood is 0.05 g/mL. The analytical range is 0.1–5.0 g/mL. The maximum within-series errors in the determination of the studied compounds are no higher than 14.1% for concentrations of 0.10 g/mL and 7.47% for concentrations of 1.0 g/mL. The maximum between-series relative errors are 5.75% for concentrations of 0.10 g/mL and 2.7% for concentrations of 1.0 g/mL. The procedure can be used in toxicological and clinical analyses. 相似文献
17.
In a long-term field study at two locations with different air pollution levels several soot-selective measurement techniques were compared with a thermochemical method which measures non-extractable carbon (NEC) detecting the evolved CO2 by means of coulometric titration. The attenuation measurement technique (aethalometer) and the aerosol photoemission method showed good correlations to NEC for concentrations ranging from 1.6g/m3 to 40.8g/m3. The specific mass absorption coefficient of black carbon with respect to NEC varied between 8.4m2/g and 13.7m2/g with respect to the measurement sites, but the value was found to remain constant at each site independent of seasonal or meteorological variations. The ratio of photoelectric signal to NEC varied between 16 fA·(g/m3)–1 and 33 fA·(g/m3)–1 depending on the age of the aerosol. The diurnal variations of that ratio showed strong similarities to the traffic patterns. Additionally a slight temperature dependence of this ratio was found for the aged aerosol with a proportionality factor of – 0.35 fA·(K·g/m3)–1. With the reflectance measurement technique (smoke shade method) reliable NEC determination was not possible for NEC concentrations 5 g/m3. 相似文献
18.
K. Rajczyk 《Journal of Thermal Analysis and Calorimetry》1988,33(3):741-747
The transformation of Ca2SiO4 was investigated with regard to the disintegration of the sinter in alumina manufacturing. DTA was applied to study the effect of the reducing atmosphere upon the course of the polymorphic transitions of Ca2SiO4, and particularly the self-disintegration process. Pure synthetic dicalcium orthosilicate and blends of pure components from the system CaO-Al2O3-SiO2-Fe2O3 were compared with technological mixtures of limestone and fly ash. Data obtained from the DTA runs allowed the specification of technical parameter for both firing and cooling of the sinter.
Zusammenfassung Die -Umwandlung in Ca2SiO4 wurde im Hinblick auf den Zerfall von Sinter in der Tonerdeproduktion untersucht. Mittels DTA wurde der Einfluß einer reduzierenden Atmosphäre auf den Verlauf der polymorphen Umwandlungen von Ca2SiO4 und insbesondere auf den Zerrieselungsprozeß verfolgt. Reines synthetisches Ca2SiO4 und Gemische reiner Komponenten des Systems CaO-Al2O3-SiO2-Fe2O3 wurden mit technischen Mischungen aus Kalk und Flugasche verglichen. Die Ergebnisse von DTA-Versuchen erlauben die Spezifizierung der technischen Bedingungen für das Brennen und Abkühlen des Sinters.
. , , . -l23-SiO2-F23 . .相似文献
19.
I. I. Kapustina A. I. Kalinovskii S. G. Polonik V. A. Stonik 《Chemistry of Natural Compounds》1987,23(2):209-213
Three new glycosides, D1, D2, and D3, have been isolated from the Far Eastern starfishDistolasterias nipon. They have been identified by chemical and physicochemical methods as 5-cholestane÷3,6,8,15,24-pentaol 3,24-di-O--D-xylopyranoside, t-cholest-22-ene-3,6,8,15,24-pentaol 3,24-di-O--D-xylopyranoside (II), and 5-cholestane-3,6,8,15,24-pentaol 24-O--D-glucopyranoside 3-O--D-xylopyranoside (III).Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 250–255, March–April, 1987. 相似文献
20.
Summary Tetramethylthiuram disulphide (TMTD) is used for the extraction and spectrophotometric determination ofg quantities of osmium. 15 ml of 1.052×10–3 M TMTD in toluene quantitatively extracts osmium from7 M HCl. The complex attains maximum colour intensity in 2 hours. It is red in colour and exhibits two max. One at 445 nm and the other at 504 nm. The maximum at 504 nm is more significant. Beer's law was found to hold good over the concentration range of 1.7 to 26.7g of osmium per ml. The Ringbom plot shows the optimum range of 9.42 to 23.65g of osmium per ml. The optimum period of equilibration is 30 seconds and the complex is stable up to 5 hours. The extracted species shows the composition to be 1 1 (Os TMTD). It is possible to extract and determine osmium in the presence of other platinum metals with composition corresponding to the ore osmiridium.
Zusammenfassung Tetramethylthiuramdisulfid (TMTD) wurde zur Extraktion und spektrophotometrischen Bestimmung von Mikrogrammengen Osmium verwendet. 15 ml einer 1,052.10–3-molaren Lösung von TMTD in Toluol dienen zur Extraktion von Os aus 7-m Salzsäure. Der entstandene rote Komplex erreicht innerhalb 2 Stunden maximale Farbintensität und zeigt zwei Absorptionsmaxima bei 445 nm und 504 nm. Letzteres ist signifikanter. Zwischen 1,7 und 26,7g Os/ml gilt das Beersche Gesetz. Nach der Ringbom-Gleichung liegt die geeignetste Konzentration zwischen 9,42 und 23,65g Os/ml. Nach 30 sec stellt sich das Gleichgewicht ein und bleibt bis zu 5 Stunden konstant. Die extrahierte Substanz entspricht der Zusammensetzung 1 1 (Os TMTD). Os läßt sich auch in Gegenwart anderer Platinmetalle so extrahieren und bestimmen.相似文献