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  • 1
    Electronic Resource
    Electronic Resource
    Differential lipid oxidation in various parts of frozen mackerel (1977)
    Oxford, UK : Blackwell Publishing Ltd
    International journal of food science & technology 12 (1977), S. 0 
    Details
    ISSN: 1365-2621
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Kinetic variations in lipid oxidation in various parts of mackerel stored at −15, −30 and −40°C were studied by measuring the changes of POV and of TBA molar values as a function of time. Oxidation developed in the skin sample (subcutaneous fat) was found to be eight times faster in TBA change than in the white and dark muscles from mackerel held at −15°C for two months. This rapid development of rancidity in the skin was effectively inhibited by lowering the frozen storage temperature to −40°C, where relatively the degree of lipid oxidation in the dark muscle was found to be of the same order of magnitude. the in vitro rate of autoxidation at 60° C for the lipids extracted from skin and the fillet muscle also showed an unusual difference which indicated that unknown pro−oxidative substances in mackerel skin were fat solvent extractable. the activity of the unknown compounds in the skin was also temperature dependent even in the frozen state, but could be effectively mitigated by lowering temperature to −40°C. Lipid hydrolysis in mackerel was also retarded completely when the fish were stored at −40° C. the comparative compositions of fatty acids and volatile carbonyls were determined in head, skin, white and dark muscle, and suggested an active non-specific oxidation system in the skin fat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1977.tb00083.x
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  • 2
    Electronic Resource
    Electronic Resource
    ACCELERATION OF LIPID OXIDATION IN FROZEN MACKEREL FILLET BY PRETREATMENT WITH MICROWAVE HEATING (1978)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 43 (1978), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fresh mackerel fillets with skin on were pretreated, before frozen storage at –15°C by microwave heating at 2450 MHz for 5, 10 and 20 sec. During 6 months, the lipids of the skin and meat of the fillets were separately examined for quality variations by chemical methods such as TBA, POV and FFA. Pro-oxidant effects on lipids in mackerel fillets pretreated for 20 sec were shown by an increase of TBA molar value of 200% and 100% in the skin and meats, respectively, after 6 wk of frozen storage at –15°C. In fillets stored for 6 months, the rate of increase in POV in the pretreated sample was twice that in the control. According to the RIM quality evaluation system, the life in frozen storage of mackerel fillets pretreated with microwave heating decreased proportionately with the time of pretreatment. The loss of storage life was as much as 60% (from 16 to 7 wk) compared with the control samples. It is suggested that the promotion of lipid oxidation in the fish pretreated with microwave energy should be considered as a particularly important factor affecting the quality during frozen preservation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1978.tb09731.x
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  • 3
    Electronic Resource
    Electronic Resource
    Kinetic method for the determination of mercury at the nanogram level using an iodide-catalyzed arsenitecerium reaction (1972)
    Springer
    Microchimica acta 60 (1972), S. 768-783 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Eine kinetische Methode zur Quecksilberbestimmung mit Hilfe der jodkatalysierten Reaktion zwischen Arsenit und Cer(IV) wurde ausgearbeitet. Der infolge der Hemmung durch Quecksilber eintretende Unterschied im Reaktionsablauf wurde spektrophotometrisch bei 275 nm gemessen. Die optimalen Reaktionsbedingungen wurden untersucht, um größere Empfindlichkeit bei der Quecksilberbestimmung zu erzielen. Die beschriebene Arbeitsweise kann mit zufriedenstellendem Erfolg für Proben angewendet werden, die 1–60 ng Hg enthalten. Der Fehler ist durchwegs geringer als 5%.
    Notes: Summary A kinetic method for the determination of mercury has been developed by using the iodide-catalyzed reaction between arsenite (III) and cerium (IV). The difference in reaction rate due to inhibition by mercury was measured spectrophotometrically at 275 nm. Optimum reaction conditions were investigated in order to obtain a greater sensitivity in the determination of mercury. The described procedure can be used satisfactorily for samples containing mercury in the 1 to 60 ng range, with an overall error of less than 5 %.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01239144
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  • 4
    Electronic Resource
    Electronic Resource
    Determination ofβ-Mercaptopyruvic acid in cysteine transamination mixture by titration with o-Hydroxymercuribenzoic acid using dithiofluorescein as an indicator (1971)
    Springer
    Microchimica acta 59 (1971), S. 531-538 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Eine rasche Methode zur direkten thiomaßanalytischen Bestimmung vonβ-Mercapto-Brenztraubensäure wurde beschrieben. o-Hydroxy-mercuribenzoesäure dient als Maßlösung mit Dithiofluorescein als Indikator. Cystein und andere Thiolverbindungen mit einer primären oder sekundären Aminogruppe können mit Formaldehyd zu Thiazolidinderivaten umgesetzt und damit inaktiviert werden.β-Mercapto-Brenztraubensäure läßt sich bis zu 0,2μMol in Gegenwart vonα-Ketoglutarat, Glutamat, Pyridoxalphosphat und Cystein auf 5% genau bestimmen. Das Verfahren eignet sich zur Bestimmung vonβ-Mercaptobrenztraubensäure, die bei der Transaminierung von Cystein mit Hilfe eines Rattenleberextraktes entsteht.
    Notes: Summary A rapid and direct thiotitrimetric method for the determination ofβ-mercaptopyruvic acid is described.o-Hydroxymercuribenzoic acid is used as a direct titrant with dithiofluorescein as an indicator. Cysteine and other thiol compounds which have a primary or secondary amino group can be inactivated by formaldehyde to form thiazolidine derivatives.β-Mercaptopyruvic acid can be successfully determined to the limit of 0.2μmol with an error less than 5% in the presence ofα-ketoglutarate, glutamate, PLP, as well as cysteine. The procedure described can be employed for the determination ofβ-mercaptopyruvic acid formed during cysteine transamination using a rat liver extract as the enzyme source.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01219066
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  • 5
    Electronic Resource
    Electronic Resource
    Anticatalytic microdetermination of mercury using cerium-arsenite reaction (1973)
    Springer
    Microchimica acta 61 (1973), S. 15-24 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Eine antikatalytische, kinetische Methode zur Quecksilberbestimmung wurde ausgearbeitet, die auf der Hemmung der Cer(IV)-As(III)-Reaktion beruht. Die Veränderung der Reaktionsgeschwindigkeit wird spektrophotometrisch bei 275 nm gemessen. Die Reaktionsbedingungen und die Störung durch Fremdionen wurden geprüft. 0,04–0,20μg Hg wurden mit einem Gesamtfehler von weniger als 5% innerhalb 25 min. bestimmt.
    Notes: Summary An anticatalytic kinetic method, based on the decreased rate of the reaction between Ce(IV) and As (III), was developed for the determination of mercury. The change in reaction rate due to inhibition by mercury was measured spectrophotometrically at 275 nm. Reaction conditions and interferences of foreign ions were studied. Amounts of mercury in the range 0.04–0.20μg were determined with an overall error of less than 5 % at a reaction time of 25 minutes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01220129
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  • 6
    Electronic Resource
    Electronic Resource
    Catalytic determination of iodine in serum at nanogram levels using the As(III)/Ce(IV) reaction (1973)
    Springer
    Microchimica acta 61 (1973), S. 569-581 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Eine katalytische Jodbestimmungsmethode auf der Grundlage der As(III)/Ce(IV)-Reaktion wurde ausgearbeitet. Die durch Jodkatalyse bedingte Differenz des Reaktionsausmaßes wurde spektralphotometrisch bei 310 nm gemessen. Das Optimum der Reaktionsbedingungen für eine größtmögliche Empfindlichkeit der Jodbestimmung wurde ermittelt. Das Verfahren kann für Jodmengen zwischen 0,4 und 10,0 ng mit Erfolg verwendet werden; der durchschnittliche Fehler beträgt weniger als 6%. Jodbestimmungen im Serum nach dieser Methode stimmen mit klinisch-chemisch ermittelten Werten gut überein.
    Notes: Summary A catalytic determination of iodine using the As(III)/Ce(IV) reaction has been developed. The difference in reaction rate due to catalysis by iodide was measured spectrophotometrically at 310 nm. Optimum reaction conditions were investigated in order to obtain a greater sensitivity in the determination of iodine. The method can be satisfactorily used for samples containing iodine in the 0.4 to 10.0 ng range, with an overall error less than 6 %. The method has been used for the determination of iodine in serum, and gives results which compare favorably with a present clinical chemistry procedure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01218002
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  • 7
    Electronic Resource
    Electronic Resource
    Kinetic micro determination of mercury in natural waters and biological materials (1973)
    Springer
    Microchimica acta 61 (1973), S. 417-427 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die nasse Veraschung zur Aufbereitung von Wasserproben und von biologischem Material für die kinetische Quecksilberbestimmung mit Hilfe der jodkatalysierten Cer-Arsenit-Reaktion wurde beschrieben. Durch Ionenaustausch an einem selektiven Harz wurde eine quecksilberfreie Vergleichsprobe hergestellt. Diese diente nach Zusatz bekannter Quecksilbermengen zur Ermittlung einer Eichkurve. Anorganisches und organisch gebundenes Quecksilber kann nach diesem Verfahren in Wasser oder biologischem Material im Bereich zwischen 0,05 und 2,0μg/ml bestimmt werden. Für die Größenordnung von 0,05 ppm kann das Verfahren für frisches Wasser und für Harn mit einem durchschnittlichen Fehler unter 5% verwendet werden. Ebenso dient es zur Untersuchung von Meerwasser und Blutserum mit einem Fehler bis zu 10%. Die Ergebnisse stehen mit denen anderer Methoden in gutem Einklang.
    Notes: Summary A wet digestion has been developed to prepare water and biological samples for a kinetic determination of mercury using an iodide-catalyzed reaction between cerium(IV) and arsenite(III). A mercury-free control, prepared using ion-exchange with a selective chelating resin, was used by adding mercury standards to make a calibration curve. Both inorganic and organic mercury can be determined by the method described either in water or biological samples containing mercury in the range of 0.05 to 2.0μg per ml. The procedure can be used satisfactorily down to the 0.05-ppm level for fresh water and urine with an overall error of less than 5 %. The method can also be employed for the determination of mercury in sea water or blood serum with an error of 10 % or less and gives results which compare favourably with other procedures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01218173
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