Möglichkeiten der Röntgenfluoreszenz- und Röntgenemissions-Spektrometrie in der Werkstoffanalytik

The principles and applications of X-ray fluorescence spectrometry and X-ray emission in the electron microprobe analysis and low energy electron induced X-ray spectrometry were described. With the help of soft X-ray spectra, arising from the valence bands, the different aluminum and titanium compounds of precipitates in steel can be investigated. The precipitates were isolated by an galvanostatic electrolysis. For speciation of aluminum the K_βlines in the X-ray fluorescence spectrum were investigated. The composition of aluminum oxide and -nitride in precipitates of special steel qualities can be determined. In the case of the speciation of titanium a direct electron bombardment of the sample is used to generate soft-X-rays. By investigating the L-lines of titanium different species like titaniumcarbide,-nitride or sulphide can be distinguished.     

Palmöl und Palmkernöl

Palm Oil and Palm Kernel Oil Adulteration of palm oil with palm stearin can be recognized by examining the ration of the triglycerides PPP to MOP, which lies in pure palm oil between 3.5 and 4.5 and is elevated in the case of adulteration. The content of palmitic acid and the solid fat content are additional indications. Adulteration of coconut and palm kernal oils with palm kernel olein is best recognized by measuring the iodine number (which is max. 11 for coconut oil and 19 for palm kernel oil) and also by the content of stearic, oleic and linoleic acids, the sum of which should not exceed 11.5% for coconut oil and 22% for palm kernel oil respectively. The content of triglycerides with carbon number 46 to 54 may additionally be used.     

Kristallstrukturuntersuchungen an Fettalkoholen und Fettsäuren mit Elektronen- und Röntgenbeugung I

Studies on Crystal Structures of Fatty Alcohols and Fatty Acids Using Electron and X-Ray Diffraction I For the homologous series of even numbered saturated fatty alcohols from dodecanol (C₁₂H₂₅OH) up to hexacosanol (C₂₆H₅₃OH) the almost orthorhombic unit cells of the β₀₁-modifications could be shown by using electron and X-ray diffraction. Fouriersynthesis based on hkO-reflexes showed the presence of a β₀₂-form which has half the edge length c compared to the β₀₁-modification. Moreover, the eight γ₃- to γ₁₀-modifications of the various alcohols were detected. Unit cell parameters and the chain tilt were determined for all crystal structures. By X-ray diffraction, stearic acid was shown to exhibit five β_n-(n = 2, 4, 5, 8) and seven γ₂- to γ₈-forms. The β_n-forms consist of molecules tilted over the short subcell a_s-axis, whereas in γ_n-forms the molecular chains are tilted over the b_s-axis. All the modifications of alcohols and fatty acids studied have an orthorhombic subcell, while the neighbouring molecules in monomolecular layers are turned to each other at an angle of about 90°.     

Die Fettsäure-Zusammensetzung von Rüböl,Sojaöl,Sonnenblumenöl und Erdnußöl

Fatty Acid Composition of Rapeseed, Soybean, Sunflower and Peanut Oils Alterations in the mode of cultivation of oilseeds have brought forth considerable fluctuations in the composition of vegetable oils in the past decade. It is therefore desirable to report occasionally the new analytical figures on vegetable oils, whose source and past history are exactly known.     

Zu den Veränderungen von Rapsöl und Leinöl während der Verarbeitung

Changes of rapeseed and linseed oil during processing During processing of crude oil in a large oil mill, three samples each of rapeseed and linseed were investigated at each processing stage, i.e. press oil, solvent-extracted oil, mixed oil, and degummed/caustic refined oil. In the case of rapeseed also bleached and desodorized oils (230°C; 3.0 mbar for 2 h) were investigated. Rapeseed and linseed oil showing the typical major fatty acids contained less than 1% trans-isomeric fatty acids (trans fatty acids = TFA). Linseed oil had a similar TFA-concentration as rapeseed oil, and the concentrations did not change during the processing stages up to degummed/caustic refined oil, and were also unchanged in the bleached rapeseed oil. Desodorization of rapeseed oil, however, trebled the TFA concentration to 0.58%. The detected tocopherol patterns were typical of rapeseed and linseed oils. There was no difference between mixed oil and degummed/caustic refined oil in the total concentration of tocopherols. Neither had bleaching any effect. Rapeseed oil desodorization diminished total tocopherol concentration by 12% from 740 mg/kg to 650 mg/kg. Due to degumming/caustic refining the phosphorus concentration of both oils decreased to less than a tenth compared to mixed oil. Other elements determined in degummed/caustic refined rapeseed oil were not detectable (manganese < 0.02 mg/kg, iron < 0.4 mg/kg, copper < 0.02 mg/kg, lead < 10 μg/kg) or only as traces zink 0.1 mg/kg, cadmium 2 μg/kg). In linseed oil, which initially showed a higher trace compounds concentration, a significant decrease was found by degumming/caustic refining. Iron could not be detected. There were traces of zinc, manganese, copper, lead, and cadmium. There was no difference between the acid values of rapeseed and linseed crude oil. Acid value decreased drastically already during the degumming/caustic refining stage. The crude linseed oils had a higher peroxide value, anisidine value and diene value than the corresponding crude rapeseed oils. With peroxide values of ≤ 0.1 mEq O₂/kg found in almost all investigated rapeseed oils, no effect of refining could be detected. The anisidine value showed an increase after bleaching. Desodorization trebled the diene value.     

Über Kaffeeöle zur Beurteilung von grünen und gerösteten Kaffeebohnen

Coffee Oils in the Assessment of Raw and Roasted Coffee Beans Increasing amounts of robusta coffee is used for the production of roasted coffee mixtures for the preparation of beverages and coffee extract powders. Owing to the differences between arabica and robusta coffee varieties with respect to composition and flavour, the detection of the latter variety is desirable. The composition of coffee oils from the arabica and robusta varieties is reported and colour reactions of the coffee oils are discussed which enable to distinguish between raw and roasted, whole and powdered beans of arabica and robusta varieties and permit the detection of robusta coffee in mixtures with arabica coffee.     

Reaktivität und Toxizität homologer Brom- und Dibromalkane

Reactivity and Toxicity of Homologous Bromo- and Dibromoalkanes The rate constants of the reactions of 4-(4-nitrobenzyl)-pyridine (NBP) with ω,ω′-dibromoalkanes Br (CH₂)_n Br (n = 2–4), alkyl bromides C_nH_2+n1Br (N = 2–4) and allyl bromide in acetophenone were measured and compared with the LD₅₀-values of these compounds estimated on mice. The tested dibromoalkanes show a contrary graduation of reactivity and acute toxicity.     

Diterpene in Kaffeeölen zur Beurteilung von Rohkaffee nach Art und Bearbeitung

Diterpenes in Coffee Oils for the Evaluation of Raw Coffee According to Type and Processing Commercial varieties of coffee are classified into the types “Arabica” and “Robusta”. Differences between these two types are shown and the possibilities for their detection on the basis of diterpenes (cahweol) are explained. Arabica types contain cahweol in varying amounts, which can be quantitatively expressed by a colour reaction. Examples are given to show that the processing of raw coffee (steaming, decoffeination, C-5-HT-reduction) leads to varying degrees of reduction of cahweol colour absorption. Thus it is possible to recognize processed raw coffee on the basis of cahweol colour reaction and to express the effects of processing. Cahweol colour reaction is a suitable indicator for processed raw coffee, especially for steamed raw coffee.     

Zur Qualität und Kontamination von Fischölkapseln

On the Quality and Contamination of Fish Oil Capsules All medicinal fish oil capsules available in German market, viz. 27 products, were examined w.r.t. their cholesterol- and lipophilic vitamine contents as well as oxidised and polymer fractions. Moreover, the possible contamination of the fish oils with organochloric pesticides, polychlorinated biphenyles (PCB), heavy metals and polycylic aromatic hydrocarbons (PAH's) was also examined. Our objective was to answer the enquires made to us by many physicians regarding the content of fish oil capsules w.r.t. cholesterol, vitamin A, vitamin D and vitamin E. At the same time we also ascertained, the extent to which these therapeutic products, conformed to the existing food legislation, the guidelines of Codex-Alimentarius and those of the fat processing industry. We found that, most of these products had a degree of oxidation amounting to abt. 20%, a 2 – 3.5% polymeric triglyceride content and a cholesterol content between 0.3 – 0.6%. The capsules contained, with very small exceptions, no vitamin A. Contrary to this, the vitamin E concentration of most products were between abt. 600 to abt. 7000 μg/g and 15 to abt. 100 IU/g vitamin D respectively. The contamination of the capsules with organochlorine pesticides, PCB and heavy metals was in line with normal level of such pollutants in fish oil, i.e. most products conformed to legal guidelines and only a few exceeded the limits. However, the PAH-contamination of most capsules, particularly with benzo(a)pyrene, did not conform with the guidelines.     

Brüdenöl aus Soja- und Rapsöl als Tocopherolen-Quelle

Post Deodorization Condensates from Soya and Rape Oils as a Source of Tocopherols For refining of different kinds of plant oils the same industrial installations are used. The qualitative and quantitative composition of tocochromanols obtained from post deodorization condensates depends on the refined oil. The influence of the quantity of refined oils in the process on quantitative changes of tocopherols in the condensates was investigated. We found, that for the eventual obtaining of tocopherol concentrates from them, it is better to use soya post deodorization condensate. The maximum concentration of tocopherols in soya condensate was found after deodorization of approximately 26 tons of the oils at an installation yield of about 3.5 tons per hour.     

Isolierung und Strukturaufklärung polyverzweigter Fettsäuren aus Fischöl

Isolation and Structure Determination of the Polybranched Fatty Acids from Fish Oil From a sample of sea fish oil, three saturated polymethyl branched fatty acids could be separated in pure state as methyl esters by using urea adduct, column chromatography and distillation methods. These could be identified as 4,8,12-trimethyl-tridecanoic acid, 2,6,10,14-tetramethyl-pentadecanoic acid and 3,7,11,15-tetramethyl-hexadecanoic acid, with the help of molecular weight determination, ultimate analysis, IR-, NMR- and mass-spectroscopy. The structures could be proved by synthesis. Many other branched chain fatty acids were synthesised for comparison. The synthesis and the infrared spectrums of these compounds are given in details.     

Schnelle und präzise Bestimmung des Gesamtglucosinolatgehaltes von Rapssamen-Vergleich der Röntgenfluoreszenzanalyse mit Gaschromatographie und Hochdruckflüssigkeitschromatographie

Rapid and Precise Determination of Total Glucosinolate Content in Rapeseed – Comparison of X-Ray Fluorescence Spectroscopy with Gaschromatography and High-Performance-Liquid-Chromatography The introduction of oilseed-rape cultivars poor in glucosinolates within the EG requires methods which allow a separation of the yield batches by the glucosinolate content. By means of the indirect determination of the glucosinolate content by X-ray-spectroscopy a method is introduced that produces a high correlation with conventional procedures (r² = 99% for GC-reference samples, r² = 92% for GC single data, r² = 96% for HPLC single data; deviations from average values: GC-reference samples 1.3%; single analyses of GC and HPLC 7.4 respectively 3.1%) and that needs only 4 minutes for one complete determination and is easily to perform.