The determination of pharmaceutically active thiols using hydrophilic interaction chromatography followed postcolumn derivatization with o -phthaldialdehyde and fluorescence detection

2018 ◽  
Vol 156 ◽  
pp. 1-7 ◽  
Author(s):  
Michal Douša
Keyword(s):  
Fluorescence Detection ◽  
Hydrophilic Interaction Chromatography ◽  
Hydrophilic Interaction ◽  
Postcolumn Derivatization

scholarly journals Single-Laboratory Validation for the Determination of Cocoa Flavanols and Procyanidins (by Degree of Polymerization DP1–7) in Cocoa-Based Products by Hydrophilic Interaction Chromatography Coupled with Fluorescence Detection: First Action 2020.05

2020 ◽  
Author(s):  
Ugo Bussy ◽  
Gregory Hewitt ◽  
Yusuf Olanrewaju ◽  
Brian R May ◽  
Nicholas Anderson ◽  
...  
Keyword(s):  
Fluorescence Detection ◽  
Degree Of Polymerization ◽  
Laboratory Method ◽  
Hydrophilic Interaction Chromatography ◽  
Hydrophilic Interaction ◽  
Wide Range ◽  
Fit For Purpose ◽  
Single Laboratory ◽  
Cocoa Flavanols

Abstract Background Flavanols and procyanidins are complex bioactives found in many foods such as cocoa. As their consumption is associated with health benefits, cocoa flavanols and procyanidins are receiving increasing attention from consumers, industry, researchers, and regulators. Objective The objective of this study is to validate a method using hydrophilic interaction chromatography (HILIC) with fluorescence detection (FLD) and a commercially available reference material for the determination of flavanols and procyanidins (CF) in cocoa-based products. Methods Method performances were evaluated for cocoa matrices with CF content that ranged from 0.8 to 500 mg/g, which included low CF matrices (milk and dark chocolate, cocoa powder, and liquor) and high CF matrices (cocoa extract and dietary supplement products). The method was validated in a single-laboratory by determining sensitivity, selectivity, linearity, stability, robustness, accuracy, and precision for each of the matrices. Results The method was validated for cocoa matrices with CF content that ranged from 0.8 to 500 mg/g. Accuracy ranged from 86 to 99% and repeatability (RSDr) from 1.5 to 8.6% for CF. Conclusions Analytical performances acquired through this single-laboratory validation study for a wide range of cocoa-based matrices demonstrate that this method is fit-for-purpose for the determination of flavanols and procyanidins in cocoa-based products. Highlights Hydrophilic interaction chromatography (HILIC) with fluorescence detection was successfully used to determine total CF content in multiple product types. Single-laboratory method validation results demonstrate that the method is fit for purpose for cocoa-based matrices containing <0.8 to 500 mg/g of CF.

Alcohol Determination by HPLC with Postcolumn Derivatization Based on the Thiosulfate-catalyzed Reaction of Alcohols and Cerium(IV) and Fluorescence Detection of Cerium(III)

2020 ◽  
Vol 16 ◽  
Author(s):  
Ikko Mikami ◽  
Eri Shibayama ◽  
Kengo Takagi
Keyword(s):  
Detection Limit ◽  
Fluorescence Detection ◽  
Reaction Rate ◽  
Detection Method ◽  
Fluorescence Detector ◽  
Reaction Solution ◽  
Optimum Detection ◽  
Postcolumn Derivatization ◽  
Sensitive Method

Background: Determination of a reducing substance based on the reaction between Ce(IV) and a reducing substance and fluorescence detection of Ce(III) generated has been reported as a selective and sensitive method. However, this method could not be applied to the determination of alcohol due to the low reaction rate of alcohol and Ce(IV). Objective: We found that thiosulfate catalytically enhanced reaction of alcohols (such as, methanol, ethanol, and propanol) and Ce(IV). Utilizing this effect, we developed a new method for the determination of alcohols. Results: In the presence of thiosulfate, an increase in fluorescence intensity was detected by injecting alcohol at concentrations of several millimolar, whereas it was not observed even at the concentration of 10% v/v (2 M for ethanol) in the absence of thiosulfate. The optimum detection conditions were determined to be 4.0 mM Ce(IV) sulfate and 0.50 mM thiosulfate, and the detection limit (S/N = 3) of ethanol under these conditions was 1 mM. In the calibration curves, changes in the slope were observed when the alcohol concentrations were approximately 10–25 mM. Using a thiosulfate solution containing ethanol as the reaction solution, a calibration curve without any change in slope was obtained, although the concentration of ethanol at the detection limit increased. The alcohols in the liquor and fuel were successfully analyzed using the proposed detection method as a postcolumn reaction. Conclusion: This new alcohol detection method using a versatile fluorescence detector can be applied to the postcolumn reaction of HPLC omitting need of time-consuming pretreatment processes.

scholarly journals Determination of Sulfonamides in Edible Salmon Tissue by Liquid Chromatography with Postcolumn Derivatization and Fluorescence Detection

1997 ◽  
Vol 80 (4) ◽  
pp. 751-755 ◽  
Author(s):  
Theresa A Gehring ◽  
Larry G Rushing ◽  
Harold C Thompson
Keyword(s):  
Acetic Acid ◽  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Coho Salmon ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Aqueous Acetic Acid ◽  
Postcolumn Derivatization

Abstract Fourteen sulfonamides—sulfanilamide, sulfadiazine, sulfathiazole, sulfapyridine, sulfam- erazine, sulfamethazine, sulfamethizole, sulfamethoxypyridazine, sulfachloropyridazine, sulfamonomethoxine, suļfadoxine, sulfamethoxazole, sulfadimethoxine, and sulfaquinoxoline—residues of which could be found in aquacultured species, were separated in <25 min by reversed-phase (C18) liquid chromatography (LC) with gradient elution. Analytes were extracted from edible salmon tissue (muscle and adhering skin) with acetonitrile—2% aqueous acetic acid, isolated with 2 liquid-liquid partitionings, and derivatized with fluorescamine after eluting from the column. The derivatives were detected by fluorescence. Recoveries (n = 4) from coho salmon fortified with sulfonamides at 5,10, and 20 ng/g tissue averaged 79.7± 7.3, 84.6 ± 7.7, and 88.2 ± 7.1%, respectively. Limits of quantitation were 5 ng/g tissue, for sulfanilamide, sulfamethoxypyridazine, and sulfaquinoxoline and 1 ng/g tissue for the remaining sulfonamides.

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