A personal computer-based gradient system for high-performance liquid chromatography with low-pressure mixing

1984 ◽  
Vol 292 (2) ◽  
pp. 412-417 ◽  
Author(s):  
Ruurd Van Der Zee ◽  
Gjalt W. Welling
2015 ◽  
Vol 4 (4) ◽  
pp. 120 ◽  
Author(s):  
St. Sabahannur ◽  
. Mursalim ◽  
Laode Asrul ◽  
Mariyati Bilang

<p>Fermentation is a very vital stage of processing mechanism to ensure the chocolate products have good taste. This study was conducted to obtain an optimal result of chocolate fermentation by determining the concentration and types of amino acid of Sulawesi and local clone cacao beans using HPLC (High Performance Liquid Chromatography) method. A <em>Randomized Completely Design </em>was used in this study. Two types of cocoa clones, Sulawesi clone and Local clone, were divided into 5 groups of treatment: without fermentation (control), fermentation for 3 days, 4 days, 5 days and 6 days. The analysis of amino acids was conducted using HPLC separation method based on the procedure at Marino et al. (2010), Nollet (1996). The measurement of amino acid performed in two phases, liquid hydrolysis, and derivatization proceeded by chromatographic analysis. Condition of HPLC was measured at 37 °C. Mobile phase contains of 60% acetonitril - AccqTag Eluent A, gradient system and the flow rate was 1.0 ml per minute. Fluorescence detector has 250 nm excitation and 395 nm emission. Injecting volume was 5 uL. The results of this study show that cocoa beans of Sulawesi clone with 6-days fermentation has higher products of aspartic acid, glutamic acid, hydrophobic amino acids (Alanine, leucine, proline, valine, isoleucine) and amino acids such as serine, glysine, histidine, treonine and lysine, while local clones of cocoa beans with 3-days fermentation produce more amino acids such as aspartic, glutamic, hydrophobic (isoleucine, leucine, valine) and amino acids such as histidine, threonine, glysine, serine and lysine.</p>


1985 ◽  
Vol 63 (8) ◽  
pp. 2110-2118 ◽  
Author(s):  
R. A. Moore ◽  
F. W. Karasek

Prefractionation procedures based on high performance liquid chromatography (hplc) and low pressure column chromatography (lpcc) were developed and applied to the separation of components in extracts of environmental samples. Effective fractionation was obtained using solvent systems based on hexane, carbon tetrachloride, dichloromethane, and ether for elution on lpcc Florisil and hplc silica columns. This facilitated the identification of over thirty compounds consisting mainly of aliphatic and polyaromatic hydrocarbons, phthalate esters, phenols, and pesticides in environmental samples extracted from water. Chromatographic background levels were minimized, and compounds whose chromatographic peaks were unresolved before fractionation were isolated into separate fractions. This afforded more highly reliable gc/ms identifications. Prefractionation also served to retard the rapid degradation of capillary columns which was caused by the injection of unfractionated samples.


2009 ◽  
Vol 6 (s1) ◽  
pp. S429-S437 ◽  
Author(s):  
Suzan Zein Alabdeen Makawi ◽  
Elrasheed Ahmed Gadkariem ◽  
Saad Mohamed Hussein Ayoub

Flavonoids were extracted by solid phase extraction (SPE) from seven floral honey samples of different botanical origin from different regions of Sudan. The flavonoids were determined by high performance liquid chromatography (HPLC) technique using photo diode array detector (PDA). An isocratic and gradient systems for the resolution, identification and quantification of five flavonoids, namely; quercetin, kaempferol, apigenin, hesperetin and isorhamnetin, were developed. Although the isocratic system resolved the five compounds, however it suffered from interference by the complex mixture of honey samples. The gradient system resolved three of five flavonoids, namely, quercetin, kaempferol, and isorhamnetin, without interference by the complex honey matrix. Two flavonoids, apigenin and hesperetin, were observed to elute at close retention times, which lead to their interference with each other when injected in a mixture; however, absorption wavelength selection was found indicative of the presence or absence of either compound. The quantification of these flavonoids was done through the calibration curves of their standards. The obtained results were compared with reported results.


1981 ◽  
Vol 36 (11-12) ◽  
pp. 1072-1074 ◽  
Author(s):  
J. Kesselmeier ◽  
D. Strack

Abstract Reversed phase high performance liquid chromatography offers an efficient and rapid method for analysis of steroidal saponins. Crude extracts from primary leaves of Avena sativa and isolated etioplasts therefrom have been resolved into four saponins (avenacosides) using a water-acetonitrile gradient system on RP-8 and monitoring the column effluent at 200 nm with an UV-detector. Detectability was found to be in the range of 50 ng avenacoside B and the detector response was linear up to 8 μg tested. The described method is applicable to studies on localization and physiology of Avena saponins during development of the primary leaf.


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