Fractionation of (Co-) Polymer Blends by Multiple Solvent Gradient Elution

Author(s):  
J. A. J. Jansen ◽  
J. H. J. van den Bungelaar ◽  
A. J. H. Leenen
Author(s):  
E. G. Rightor

Core edge spectroscopy methods are versatile tools for investigating a wide variety of materials. They can be used to probe the electronic states of materials in bulk solids, on surfaces, or in the gas phase. This family of methods involves promoting an inner shell (core) electron to an excited state and recording either the primary excitation or secondary decay of the excited state. The techniques are complimentary and have different strengths and limitations for studying challenging aspects of materials. The need to identify components in polymers or polymer blends at high spatial resolution has driven development, application, and integration of results from several of these methods.


Author(s):  
William A. Heeschen

Two new morphological measurements based on digital image analysis, CoContinuity and CoContinuity Balance, have been developed and implemented for quantitative measurement of morphology in polymer blends. The morphology of polymer blends varies with phase ratio, composition and processing. A typical morphological evolution for increasing phase ratio of polymer A to polymer B starts with discrete domains of A in a matrix of B (A/B < 1), moves through a cocontinuous distribution of A and B (A/B ≈ 1) and finishes with discrete domains of B in a matrix of A (A/B > 1). For low phase ratios, A is often seen as solid convex particles embedded in the continuous B phase. As the ratio increases, A domains begin to evolve into irregular shapes, though still recognizable as separate domains. Further increase in the phase ratio leads to A domains which extend into and surround the B phase while the B phase simultaneously extends into and surrounds the A phase.


Polymer News ◽  
2005 ◽  
Vol 30 (9) ◽  
pp. 296-300
Author(s):  
F. Esposito ◽  
V. Casuscelli ◽  
M. V. Volpe ◽  
G. Carotenuto ◽  
L. Nicolais

1990 ◽  
Vol 51 (2) ◽  
pp. 185-200 ◽  
Author(s):  
Zhen-Gang Wang ◽  
S.A. Safran

1989 ◽  
Vol 50 (3) ◽  
pp. 245-253 ◽  
Author(s):  
M.G. Brereton ◽  
T.A. Vilgis
Keyword(s):  

Author(s):  
Klimenko Lina Yu ◽  
Shkarlat Galyna L ◽  
Shovkova Zoia V ◽  
Yaremenko Vitaliy D ◽  
Shpychak Oleg S

Metronidazole is the most popular representative of antiprotozoal medicines from the group of 5-nitroimidazoles. Metronidazole blocks the enzymes of alcohol dehydrogenase and acetaldehyde dehydrogenase, therefore when its joint taking with alcohol it is observed the strong intoxication syndrome and fatal poisonings too. Therefore metronidazole can be a potential object of chemical toxicological investigations. The purpose of our paper is to develop HPLC/UV-procedure of metronidazole quantification with application of the system of HPLC-analyzer MiLiChrome® A-0230 implemented in practice of forensic medical laboratories in Russia and Ukraine and carry out step-by-step validation of the developed procedure. Chromatographic conditions: Eluent A (0.2 M LiClO4 – 0.005 M HClO4) and Eluent B (acetonitrile) wereused as the mobile phase components; HPLC microcolumn Ø2×75 mm and ProntoSIL 120-5-C18 AQ, 5 μm were used as an analytical column; temperature was 40°С; flow rate was 100 μl/min; gradient elution mode was from 5% to 100% Eluent B for 40 min, then 100% Eluent B for 3 min; detection was performed at 277 nm. Retention time for metronidazole is 5.95 min. Since metronidazole is easy soluble and stable enough in the solutions of diluted alkalis 0.001 M sodium hydroxide solution has been proposed for preparation of the solutions in developing HPLC/UV-procedure of metronidazole quantification. Validation of the procedure has been carried out in the variants of the method of calibration curve and method of standard by such parameters as in process stability, linearity/calibration model, accuracy and precision within 3 different analytical runs using different batches of reagents and different glassware; experiments have been performed by three different analysts. New procedure of metronidazole quantitative determination by the method of HPLC/UV has been developed. Its validation has been carried out and acceptability for application has been shown.


2003 ◽  
Vol 18 (2) ◽  
pp. 151-155 ◽  
Author(s):  
L. S. Pinchuk ◽  
V. A. Goldade ◽  
A. G. Kravtsov ◽  
S. V. Zotov ◽  
B. Jurkowski ◽  
...  

2019 ◽  
Vol 69 (12) ◽  
pp. 3590-3592
Author(s):  
Nela Bibire ◽  
Romeo Iulian Olariu ◽  
Luminita Agoroaei ◽  
Madalina Vieriu ◽  
Alina Diana Panainte ◽  
...  

Active pharmaceutical ingredients such as isoniazid, pyrazinamide and rifampicin are among the most important first-line anti-tuberculosis drugs. A simple, rapid and sensitive reversed phase-high performance liquid chromatographic assay method for the simultaneous determination of isoniazid, pyrazinamide and rifampicin has been developed. Separation of the interest compounds was achieved in a 10 min chromatographic run in gradient elution mode on a Zorbax SB-C18 stainless steel column (150 � 4 mm, 5 mm) using a guard column containing the same stationary phase. The gradient elution was carried out with a mobile phase of 10% CH3CN aqueous solution for channel A and 50% CH3CN in pH = 6.8 phosphate buffer (20 mM), to which 1.5 mL triethylamine were added for channel B. Quantification of the analyzed substances was carried out spectrophotometrically at 269 nm. Detection limits of 0.48 mg/L for isoniazid, 0.52 mg/L for pyrazinamide and 0.48 mg/L for rifampicin were established for the developed assay method. The present work showed that the proposed analysis method was advantageous for simple and rapid analysis of the active pharmaceutical ingredients in pharmaceuticals and biological fluids.


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