Untersuchungen zur Bestimmung von Spurenelementen in Blutserum mit Hilfe der Totalreflexions-R?ntgenfluoreszenzanalyse

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     

Semiquantitative estimation of the mycotoxins citrinin, Ochratoxin A, Aflatoxin M1 and penicillic acid on thin-layer chromatograms with a grey scale

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.

     

Trace analysis of cationic surfactants in water using HPLC with conductometric detection

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.     

Influence of olefins on the catalytic transformation of paraffins on acidic zeolites

The activity and selectivity of zeolites in n-octane cracking in a gradientless flow reactor and in a flow-circulation setup with intermediate hydrogenation have been studied. At concentrations lower or equal to 10^–3 mmol/l, olefins are not involved in the cleavage of paraffin molecules. At concentrations higher than 10^–3 mmol/l, olefins act as promoters of the cracking reactions.

---

- - . , 10^–3 / . 10^–3 / .

     

Synthesis,characterization and crystal structures of heterometallic trinuclear carbonyl sulfido clusters (η5-Cp)MoFeCo- (CO)8(μ3-S) and [(η5-Cp)Mo]2Fe(CO)7(μ3-S)

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.     

Anwendung der Ringofenmethode zum Nachweis einiger Heteroelemente in organischen Verbindungen

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.

     

Fällungsanalyse im Mikrogrammbereich: Eine neue Methode

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.

     

Human prostate specific antigen (hPSA) purification and establishment of hPSA radioimmunoassay

Human prostate specific antigen (hPSA) RIA was developed with hPSA and anti-PSA prepared in our laboratory. Its standard curve was linear with a sensitivity of 0.5 g/L. Serum PSA levels of 130 normal males ranged from 0 to 3.5 g/L (1.15±0.93 g/L), which are consistent with the results of other conventional RIA. The recovery, intra- and inter-assay coefficients of variation conform to the demands of RIA, and the results of 41 samples obtained by both the PSA RIA and PSA RIA of DPC were well correlated (=0.990). PSA level of 23 patients with prostatic carcinoma was 10400 g/L.     

n-Hexane cracking over heteropoly acids, 2. Catalytic activity and thermal stability of H4SiW12O40, H6P2W18O62 and H6P2W21O71(H2O)3

The catalytic activity of three heteropoly acids has been studied in n-hexane cracking. Only H₄SiW₁₂O₄₀ does not decompose into oxides at the reaction temperature. Its acidic form is active in cracking but its dehydration leads to an inactive compound.

---

-. H₄SiW₁₂O₄₀ . , .

     

Influence of carbonate upon adsorption and isomerization of n-butenes on zeolite ZnA. Some conclusions from an infrared study

Upon the formation of carbonates inside zeolite ZnA, weakly bound species of adsorbed n-butenes are observed together with a significant change in the catalytic behavior.

---

. ZnA - .

     

Controlled-potential coulometric studies on fluoride and sulphate complexes of neptunium (VI)

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.     

Nuclear interferences of uranium and thorium in a reactor neutron activation analysis determination of cerium using the radionuclides141Ce and143Ce

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.     

Ein Beitrag zur quantitativen aktivierungsanalytischen Reinheitsbestimmung von Seltenerdoxiden

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 EuO_1,5/mg GdO_1,5; 1,2 g PrO_1,83/mg NdO_1,5 und 1,5 g LuO_1,5/mg YbO_1,5.

---

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 EuO_1,5/mg GdO_1,5; 1,2 g PrO_1,83/mg NdO_1,5, and 1,5 g LuO_1,5/mg YbO_1,5 respectively.

     

Determination of Promedol (Trimeperidine) and Ketamine in Blood Using Gas Chromatography–Mass Spectrometry

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.     

Zur coulometrischen Chloridbestimmung in konzentrierten S?uren mit potentiometrischer Indizierung und Polarisationsspannungsindikation

Zusammenfassung Die coulometrische Bestimmung geringer Chloridmengen im Gemisch von Methanol und 35%iger Schwefelsäure, 53%iger Phosphorsäure oder 37%iger Perchlorsäure kann ohne den Zusatz eines Leitelektrolyten sowohl mit potentiometrischer Indizierung als auch mit Polarisationsspannungsindikation vorgenommen werden. Das Verfahren mit potentiometrischer Indizierung, bei dem sich das Gesamttitrationsvolumen aus 10 ml Säure und 40 ml Methanol zusammensetzt, erlaubt die Bestimmung von 2,0 g/ml mit einer relativen Standardabweichung von 0,5%. Die kleinste noch bestimmbare Konzentration liegt bei 1,0 g/ml. Eine Erweiterung des erfaßbaren Konzentrationsbereiches ermöglicht die Anwendung der Polarisationsspannungsindikation. Im Gemisch von 1 ml Säure und 8 ml Methanol können noch 0,4 g/ml mit guter Genauigkeit titriert werden. Bei 2,0 g/ml Chlorid beträgt die relative Standardabweichung 2%. Für die Konzentration an der Nachweisgrenze errechnet sich 0,08 g/ml.

---

Summary The coulometric estimation of small contents of chloride in a mixture of methyl alcohol and 35% sulphuric, 53% phosphoric or 37% perchloric acids can be performed without adding any supporting electrolyte. Both the two coulometric methods, with potentiometric indication as well as by indicating the end point with two identical electrodes polarized by practically constant current can be used. The potentiometric indication method, whereby the total titration volume consists of 10 ml of acid und 40 ml of methyl alcohol, permits the determination of 2.0 g/ml chloride with a relative standard deviation of 0.5%. The smallest concentration which is just possible to be determined is 1 g/ml. By application of the second coulometric method the estimation limit can be minimized. In a mixture of 1 ml of acid and 8 ml of methyl alcohol, it is possible to titrate 0,4 g/ml. The relative standard deviation for the concentration of 2,0 g/ml has been found to be 2%. The limit of detection is 0.08 g/ml.

---

---

Herrn Prof. Dr. M. von Stackelberg zum 70. Geburtstag gewidmet.

---

Wir danken Herrn Chem.-Ing. K. Zinke für seine Mitarbeit.     

Simultaneous determination of neodymium and erbium in rare earth mixture with 5,7-dibromo-8-hydroxyquinoline and TX-100 by third-derivative spectrophotometry

The absorption spectra of 4f electron transitions of the complexes of neodymium and erbium with 5,7-dibromo-8-hydroxyquinoline in the presence of octylphenol poly(ethyleneglycol)ether have been studied by normal and third-derivative spectrophotometry. The proposed method is free of interference of other rare earths. The calibration graphs were linear up to 18 g/ml of neodymium and 21 g/ml of erbium (in the final solution). The derivative molar absorptivities are 395 l.mol^–1.cm^–1 for neodymium and 3421.mol^–1.cm^–1 for erbium. The corresponding values of Sandell's sensitivity were 0.36 and 0.49 g.cm^–1, respectively. The relative standard deviations evaluated from ten independent determinations of 2.5 g/ml of neodymium and erbium are 1.5 and 3.8% for neodymium and 1.8 and 4.1% for erbium in absence and presence of 70 g of lanthanum, respectively. The detection limits (signal to noise ratio=2) are 0.23 g/ml for neodymium and 0.30 g/ml for erbium. The method has been used for the determination of neodymium and erbium in mixed rare earths with satisfactory results.     

Thorium in man and environment uptake and clearance

The intake and tissue distribution of thorium (^{2 3 2}Th) 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 of^{2 3 3}Pa which is the activation product of^{2 3 2}Th, 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.     

Simultaneous determination of copper,mercury and lead by first-order derivative spectrophotometry using dithizone as reagent

A first-order derivative spectrophotometric method has been developed for the simultaneous determination of copper, mercury and lead at g/L levels using dithizone as reagent. The procedure involves the simultaneous extraction of these elements by dithizone in chloroform from weakly alkaline solutions. Linear calibration curves were obtained in the ranges 0.5–10 (Cu), 1–10 (Hg) and 1–10 (Pb) g present in 40 ml of aqueous phase with detection limits of 5 g/L (Cu) and 20 g/L (Hg and Pb). The R.S.D.s for 100 g/L of copper, mercury and lead were 2.5, 2.6 and 3.1% respectively, for 5 determinations. The method is applicable for the determination of copper and lead in marine sediment samples with good precision and accuracy.     

A toxic reagent-free method for normal-phase matrix solid-phase dispersion extraction and reversed-phase liquid chromatographic determination of aldrin,dieldrin, and DDTs in animal fats

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.