scholarly journals The Use of Electrochemical Voltammetric Techniques and High-Pressure Liquid Chromatography to Evaluate Conjugation Efficiency of Multiple Sclerosis Peptide-Carrier Conjugates

2020 ◽  
Vol 10 (9) ◽  
pp. 577 ◽  
Author(s):  
Efstathios Deskoulidis ◽  
Souzana Petrouli ◽  
Vasso Apostolopoulos ◽  
John Matsoukas ◽  
Emmanuel Topoglidis

Recent studies have shown the ability of electrochemical methods to sense and determine, even at very low concentrations, the presence and quantity of molecules or analytes including pharmaceutical samples. Furthermore, analytical methods, such as high-pressure liquid chromatography (HPLC), can also detect the presence and quantity of peptides at very low concentrations, in a simple, fast, and efficient way, which allows the monitoring of conjugation reactions and its completion. Graphite/SiO2 film electrodes and HPLC methods were previously shown by our group to be efficient to detect drug molecules, such as losartan. We now use these methods to detect the conjugation efficiency of a peptide from the immunogenic region of myelin oligodendrocyte to a carrier, mannan. The HPLC method furthermore confirms the stability of the peptide with time in a simple one pot procedure. Our study provides a general method to monitor, sense and detect the presence of peptides by effectively confirming the conjugation efficiency. Such methods can be used when designing conjugates as potential immunotherapeutics in the treatment of diseases, including multiple sclerosis.

1977 ◽  
Vol 60 (2) ◽  
pp. 279-283
Author(s):  
Ronald G Luchtefeld

Abstract The high pressure liquid chromatographic (HPLC) method is capable of detecting from 1 to 0.024 ppm methyl 3-(2-quinoxalinyl-methylene) carhazate-Nl,N4-dioxido (carbadox). Carbadox is extracted from the feed with 2% NH4OH in acetone, passed through a liquid-liquid partition, subjected to HPLC, and detected by using a 365 nm detector. No feed materials or other active drug ingredients produced false positive results.


2010 ◽  
Vol 73 (6) ◽  
pp. 1073-1076 ◽  
Author(s):  
MARY ANN DOMBRINK-KURTZMAN ◽  
STEPHEN M. POLING ◽  
DAVID F. KENDRA

The presence of deoxynivalenol (DON) in cereal-based baby food, a primary source of the first solid food for infants, was studied in order to develop a method to detect its presence at low concentrations. DON, produced primarily by Fusarium graminearum, is commonly isolated from grains and feed around the world and affects both animal and human health, producing diarrhea, vomiting, gastrointestinal inflammation, and immunomodulation. An aqueous extract of infant cereal was cleaned by means of an immunoaffinity chromatography column. After the eluate was evaporated and redissolved, DON was determined by high-pressure liquid chromatography–UV. The level of quantification for DON was 10 ppb for three types of infant cereal (mixed, barley, and oatmeal); the level of detection was 5 ppb. The protocol we have developed can measure DON between 10 to 500 ppb. An advisory level of 1 ppm for wheat products has been established by the U.S. Food and Drug Administration; however, the European Communities (EC) regulations have been set at 200 ppb for cereal-based foods for infants. Only 1 of 52 samples of barley-, mixed-, or oat-based infant cereal purchased in 2008 and 2009 in the United States exceeded the European standard.


1978 ◽  
Vol 88 (1) ◽  
pp. 157-163 ◽  
Author(s):  
R. B. Taylor ◽  
K. E. Kendle

ABSTRACT A new high pressure liquid chromatography (HPLC) method for the determination of progesterone in the presence of other Δ43-ketosteroids is described. Using this method it is shown that the rate of production of progesterone from pregn-5-ene-3,20-dione by rat ovarian homogenate is initially rapid but falls to zero within 10 min. Experiments indicate that the inhibition is due to the progesterone formed. Inclusion of RMI 12,936 with the pregn-5-ene-3,20-dione substrate results in a lower final level of progesterone and continuous production of 7α-methyltestosterone. The reduction in the levels of progesterone in presence of RMI 12,936 corresponds closely to the reduction in plasma progesterone in vivo following administration of RMI 12,936 described preivously.


1981 ◽  
Vol 64 (1) ◽  
pp. 139-143
Author(s):  
John L Iverson ◽  
Martin P Bueno

Abstract A method has been developed for separation and determination of 5 sugars in foods. Mixtures of sugars were separated by high pressure liquid chromatography (HPLC) with a μBondapak/carbohydrate column and acetonitrile-water (80 + 20) as the mobile phase. For the gas-liquid chromatographic (GLC) determination, the sugars were reacted with hydroxylamine hydrochloride to give the oximes, which were then converted to trimethylsilyl derivatives. The derivatives were separated on an 8 ft column containing 3% JXR as the liquid phase. The GLC preparative time was considerably longer than that for HPLC. Both methods were applied to the determination of fructose, glucose, sucrose, maltose, and lactose in processed foods. Recovery studies showed better accuracy for the HPLC method. Because of incomplete derivatization and/or the formation of anomers, the GLC method was not applicable to all foods.


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