scholarly journals Seasonal variation, method of determination of bovine milk stability, and its relation with physical, chemical, and sanitary characteristics of raw milk

2017 ◽  
Vol 46 (4) ◽  
pp. 340-347 ◽  
Author(s):  
Sandro Charopen Machado ◽  
Vivian Fischer ◽  
Marcelo Tempel Stumpf ◽  
Sheila Cristina Bosco Stivanin
Keyword(s):  
Seasonal Variation ◽  
Bovine Milk ◽  
Raw Milk ◽  
Variation Method ◽  
Physical Chemical ◽  
Method Of Determination

Extracts from the Scientific and Technical Press

1927 ◽  
Vol 31 (197) ◽  
pp. 445-473
Author(s):  
R.T.P.
Keyword(s):  
Aromatic Compounds ◽  
Test Bench ◽  
Chemical Study ◽  
Optical Methods ◽  
Physical Chemical ◽  
Method Of Determination ◽  
Systematic Determination ◽  
Cyclic Compounds ◽  
High Latent Heat

Physical–chemical study of light fuels and of lubricants in Aeronautics. (M. Moutte, La Technique Aeronautique, Sept.–Oct., 1926, pp. 279-281 and 305-319) (8.51/5096 France)Systematic tests of fuels in an engine on the test bench were commenced in 1917, in conjunction with a systematic determination of physical properties, and as far as possible of chemical composition. It was found that homogeneity, volatility and high latent heat of evaporisation were the most desirable qualities. In agreement with Ricardo, the aromatic compounds of hydrogen are found to be the least amenable to propagation of explosion, then the saturated cyclic compounds, and lastly the saturated acyclic compounds. In identifying fuels use is made of characteristic curves of distillation:—Temperature—Volume Distilled, Density;—Volume Distilled.Temperature—Density, Temperature—Solubility.Temperature of distillation plotted against critical temperature of solubility in aniline gives highly characteristic differences, and is considered a fundamental method. Optical methods are also used for approximate quantitative determination. The formation of clouds of condensed drops affords another method of determination. The mechanical conditions were also examined:—Variation of inlet pressure, condensation, centrifugal separation.

scholarly journals Liquid Chromatographic Determination of Diminazene Diaceturate (Berenil™) in Raw Bovine Milk

2003 ◽  
Vol 86 (5) ◽  
pp. 930-934 ◽  
Author(s):  
José E Roybal ◽  
Allen P Pfenning ◽  
Joseph M Storey ◽  
Steve A Gonzales ◽  
Sherri B Turnipseed
Keyword(s):  
Solid Phase ◽  
Bovine Milk ◽  
Raw Milk ◽  
Chromatographic Determination ◽  
Extraction Column ◽  
Simple Liquid ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple liquid chromatographic (LC) method is presented for the determination of diminazene (DZ) in raw bovine milk. DZ is extracted from raw milk by chilled aqueous centrifugation and is isolated from milk components on a cyano solid-phase extraction column. DZ is eluted by using a methanol-ion pairing reagent. A Phenomenex LUNA CN column and an acetonitrile-buffered mobile phase with a counter ion are used for gradient LC. The LC effluent is monitored at a detection wavelength of 372 nm by using a deuterium lamp. Under the parameters described, the retention time of DZ is 8–10 min with a peak area response of 6.5 mAU/ng. The method demonstrated excellent precision over all levels tested (25–400 ppb) with an overall average recovery of 90.4 ± 14.5%. The method is applicable to the monitoring of milk for DZ residues at the 25 ppb level with a limit of quantitation of 10 ppb.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

Development of a method for multielemental determination in water by EDXRF with radioisotopic source of 238Pu.

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Camilo Fuentes Serrano ◽  
Juan Reinaldo Estevez Alvares ◽  
Alfredo Montero Alvarez ◽  
Ivan Pupo Gonzales ◽  
Zahily Herrero Fernandez ◽  
...  
Keyword(s):  
Thin Layer ◽  
Expanded Uncertainty ◽  
Considerable Decrease ◽  
X Ray ◽  
Precipitation Efficiency ◽  
Method Of Determination ◽  
Sensitivity Curves ◽  
Order Of Magnitude ◽  
Metrological Parameters

A method for determination of Cr, Fe, Co, Ni, Cu, Zn, Hg and Pb in waters by Energy Dispersive X Ray Fluorescence (EDXRF) was implemented, using a radioisotopic source of 238Pu. For previous concentration was employed a procedure including a coprecipitation step with ammonium pyrrolidinedithiocarbamate (APDC) as quelant agent, the separation of the phases by filtration, the measurement of filter by EDXRF and quantification by a thin layer absolute method. Sensitivity curves for K and L lines were obtained respectively. The sensitivity for most elements was greater by an order of magnitude in the case of measurement with a source of 238Pu instead of 109Cd, which means a considerable decrease in measurement times. The influence of the concentration in the precipitation efficiency was evaluated for each element. In all cases the recoveries are close to 100%, for this reason it can be affirmed that the method of determination of the studied elements is quantitative. Metrological parameters of the method such as trueness, precision, detection limit and uncertainty were calculated. A procedure to calculate the uncertainty of the method was elaborated; the most significant source of uncertainty for the thin layer EDXRF method is associated with the determination of instrumental sensitivities. The error associated with the determination, expressed as expanded uncertainty (in %), varied from 15.4% for low element concentrations (2.5-5 μg/L) to 5.4% for the higher concentration range (20-25 μg/L).

Sign in / Sign up

Export Citation Format

Share Document