Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 

Saved Queries

Sign in to use this feature.

Search Filter Reset All

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
Add Subjects Reset
Select Subjects

Journals

remove_circle_outline
remove_circle_outline
remove_circle_outline
Add Journals Reset
Select Journals

Article Types

remove_circle_outline
remove_circle_outline
remove_circle_outline
Add Article Types Reset
Select Article Types

Countries / Regions

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
Add Countries / Regions Reset
Select Countries / Regions
Update Search
share announcement

Search Results (8)

Search Parameters:
Authors = Joselito P. Quirino

Order results
Result details
Results per page
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
14 pages, 2218 KiB  
Article
High Performance Liquid Chromatography versus Stacking-Micellar Electrokinetic Chromatography for the Determination of Potentially Toxic Alkenylbenzenes in Food Flavouring Ingredients
by Huynh N. P. Dang and Joselito P. Quirino
Molecules 2022, 27(1), 13; https://doi.org/10.3390/molecules27010013 - 21 Dec 2021
Cited by 7 | Viewed by 3364
Abstract
Alkenylbenzenes, including eugenol, methyleugenol, myristicin, safrole, and estragole, are potentially toxic phytochemicals, which are commonly found in foods. Occurrence data in foods depends on the quality of the analytical methodologies available. Here, we developed and compared modern reversed-phase high performance liquid chromatography (HPLC) [...] Read more.
Alkenylbenzenes, including eugenol, methyleugenol, myristicin, safrole, and estragole, are potentially toxic phytochemicals, which are commonly found in foods. Occurrence data in foods depends on the quality of the analytical methodologies available. Here, we developed and compared modern reversed-phase high performance liquid chromatography (HPLC) and stacking-micellar electrokinetic chromatography (MEKC) methods for the determination of the above alkenylbenzenes in food flavouring ingredients. The analytical performance of HPLC was found better than the stacking-MEKC method. Compared to other HPLC methods found in the literature, our method was faster (total run time with conditioning of 15 min) and able to separate more alkenylbenzenes. In addition, the analytical methodology combining an optimized methanol extraction and proposed HPLC was then applied to actual food flavouring ingredients. This methodology should be applicable to actual food samples, and thus will be vital to future studies in the determination of alkenylbenzenes in food. Full article
(This article belongs to the Special Issue Applications of Analytical Separations in Foods and Medicinal Products)
►▼ Show Figures

Figure 1

24 pages, 2542 KiB  
Review
Bile Salts in Chiral Micellar Electrokinetic Chromatography: 2000–2020
by Raymond B. Yu and Joselito P. Quirino
Molecules 2021, 26(18), 5531; https://doi.org/10.3390/molecules26185531 - 12 Sep 2021
Cited by 12 | Viewed by 2865
Abstract
Bile salts are naturally occurring chiral surfactants that are able to solubilize hydrophobic compounds. Because of this ability, bile salts were exploited as chiral selectors added to the background solution (BGS) in the chiral micellar electrokinetic chromatography (MEKC) of various small molecules. In [...] Read more.
Bile salts are naturally occurring chiral surfactants that are able to solubilize hydrophobic compounds. Because of this ability, bile salts were exploited as chiral selectors added to the background solution (BGS) in the chiral micellar electrokinetic chromatography (MEKC) of various small molecules. In this review, we aimed to examine the developments in research on chiral MEKC using bile salts as chiral selectors over the past 20 years. The review begins with a discussion of the aggregation of bile salts in chiral recognition and separation, followed by the use of single bile salts and bile salts with other chiral selectors (i.e., cyclodextrins, proteins and single-stranded DNA aptamers). Advanced techniques such as partial-filling MEKC, stacking and single-drop microextraction were considered. Potential applications to real samples, including enantiomeric impurity analysis, were also discussed. Full article
(This article belongs to the Special Issue Chiral Separation by Chromatographic and Electrophoretic Methods Applied in the Enantioseparation of Pharmaceuticals)
►▼ Show Figures

Figure 1

25 pages, 1824 KiB  
Review
Analytical Separation of Carcinogenic and Genotoxic Alkenylbenzenes in Foods and Related Products (2010–2020)
by Huynh N. P. Dang and Joselito P. Quirino
Toxins 2021, 13(6), 387; https://doi.org/10.3390/toxins13060387 - 28 May 2021
Cited by 10 | Viewed by 4546
Abstract
Alkenylbenzenes are potentially toxic (genotoxic and carcinogenic) compounds present in plants such as basil, tarragon, anise star and lemongrass. These plants are found in various edible consumer products, e.g., popularly used to flavour food. Thus, there are concerns about the possible health consequences [...] Read more.
Alkenylbenzenes are potentially toxic (genotoxic and carcinogenic) compounds present in plants such as basil, tarragon, anise star and lemongrass. These plants are found in various edible consumer products, e.g., popularly used to flavour food. Thus, there are concerns about the possible health consequences upon increased exposure to alkenylbenzenes especially due to food intake. It is therefore important to constantly monitor the amounts of alkenylbenzenes in our food chain. A major challenge in the determination of alkenylbenzenes in foods is the complexity of the sample matrices and the typically low amounts of alkenylbenzenes present. This review will therefore discuss the background and importance of analytical separation methods from papers reported from 2010 to 2020 for the determination of alkenylbenzenes in foods and related products. The separation techniques commonly used were gas and liquid chromatography (LC). The sample preparation techniques used in conjunction with the separation techniques were various variants of extraction (solvent extraction, liquid-liquid extraction, liquid-phase microextraction, solid phase extraction) and distillation (steam and hydro-). Detection was by flame ionisation and mass spectrometry (MS) in gas chromatography (GC) while in liquid chromatography was mainly by spectrophotometry. Full article
(This article belongs to the Special Issue Detection and Control of Plant and Fungal Metabolites: An Application in Human Life)
►▼ Show Figures

Figure 1

12 pages, 3568 KiB  
Article
Metabolic Stability of New Mito-Protective Short-Chain Naphthoquinones
by Zikai Feng, Jason A. Smith, Nuri Gueven and Joselito P. Quirino
Pharmaceuticals 2020, 13(2), 29; https://doi.org/10.3390/ph13020029 - 12 Feb 2020
Cited by 5 | Viewed by 3141
Abstract
Short-chain quinones (SCQs) have been identified as potential drug candidates against mitochondrial dysfunction, which is largely dependent on their reversible redox characteristics of the active quinone core. We recently synthesized a SCQ library of > 148 naphthoquinone derivatives and identified 16 compounds with [...] Read more.
Short-chain quinones (SCQs) have been identified as potential drug candidates against mitochondrial dysfunction, which is largely dependent on their reversible redox characteristics of the active quinone core. We recently synthesized a SCQ library of > 148 naphthoquinone derivatives and identified 16 compounds with enhanced cytoprotection compared to the clinically used benzoquinone idebenone. One of the major drawbacks of idebenone is its high metabolic conversion in the liver, which significantly restricts its therapeutic activity. Therefore, this study assessed the metabolic stability of the 16 identified naphthoquinone derivatives 1–16 using hepatocarcinoma cells in combination with an optimized reverse-phase liquid chromatography (RP-LC) method. Most of the derivatives showed significantly better stability than idebenone over 6 hours (p < 0.001). By extending the side-chain of SCQs, increased stability for some compounds was observed. Metabolic conversion from the derivative 3 to 5 and reduced idebenone metabolism in the presence of 5 were also observed. These results highlight the therapeutic potential of naphthoquinone-based SCQs and provide essential insights for future drug design, prodrug therapy and polytherapy, respectively. Full article
(This article belongs to the Section Pharmacology)
►▼ Show Figures

Graphical abstract

2 pages, 297 KiB  
Editorial
We’ve Come a Long Way, Baby: Announcing a Special Issue to Commemorate the Publication of Molecule’s 20,000th Paper
by Farid Chemat, Roman Dembinski, Arnaud Gautier, James W. Gauld, Derek McPhee, Diego Muñoz-Torrero, Joselito P. Quirino, Thomas J. Schmidt, Vadim A. Soloshonok and Mark von Itzstein
Molecules 2020, 25(1), 173; https://doi.org/10.3390/molecules25010173 - 31 Dec 2019
Viewed by 2243
Abstract
On behalf of my Section Editor-in-Chief co-author colleagues I am pleased to announce a Special Issue to commemorate the recent publication of Molecules’ 20,000th paper [...] Full article
(This article belongs to the Special Issue Feature Papers to Celebrate Molecules Reaches 20,000 Articles Milestone)
►▼ Show Figures

Figure 1

12 pages, 1813 KiB  
Article
Pressurized Hot Water Extraction and Capillary Electrophoresis for Green and Fast Analysis of Useful Metabolites in Plants
by Kurt Debruille, Jason A. Smith and Joselito P. Quirino
Molecules 2019, 24(13), 2349; https://doi.org/10.3390/molecules24132349 - 26 Jun 2019
Cited by 6 | Viewed by 3291
Abstract
The search for useful compounds from plants is an important research area. Traditional screening that involves isolation and identification/quantitation is tedious, time consuming, and generates a significant amount of chemical waste. Here, we present a simple, fast, and green strategy to assess ≥0.1% [...] Read more.
The search for useful compounds from plants is an important research area. Traditional screening that involves isolation and identification/quantitation is tedious, time consuming, and generates a significant amount of chemical waste. Here, we present a simple, fast, and green strategy to assess ≥0.1% wt/wt quantities of useful compounds in plants/spices using pressurized hot water extraction using a household espresso machine followed by chemical analysis using capillary electrophoresis. Three demonstrations with polygodial, cinnamaldehyde, coumarin, and shikimic acid as target metabolites are shown. Direct analysis of extracts was by the developed micellar electrokinetic chromatography and capillary zone electrophoresis methods. The approach, which can be implemented in less developed countries, can process many samples within a day, much faster than traditional techniques that would normally take at least a day. Finally, 0.8–1.1% wt/wt levels of shikimic acid were found in Tasmanian-pepperberry and Tasmanian-fuschia leaves via the approach. Full article
(This article belongs to the Section Analytical Chemistry)
►▼ Show Figures

Graphical abstract

18 pages, 2622 KiB  
Review
Chiral Selectors in Capillary Electrophoresis: Trends during 2017–2018
by Raymond B. Yu and Joselito P. Quirino
Molecules 2019, 24(6), 1135; https://doi.org/10.3390/molecules24061135 - 21 Mar 2019
Cited by 84 | Viewed by 7861
Abstract
Chiral separation is an important process in the chemical and pharmaceutical industries. From the analytical chemistry perspective, chiral separation is required for assessing the fit-for-purpose and the safety of chemical products. Capillary electrophoresis, in the electrokinetic chromatography mode is an established analytical technique [...] Read more.
Chiral separation is an important process in the chemical and pharmaceutical industries. From the analytical chemistry perspective, chiral separation is required for assessing the fit-for-purpose and the safety of chemical products. Capillary electrophoresis, in the electrokinetic chromatography mode is an established analytical technique for chiral separations. A water-soluble chiral selector is typically used. This review therefore examines the use of various chiral selectors in electrokinetic chromatography during 2017–2018. The chiral selectors were both low and high (macromolecules) molecular mass molecules as well as molecular aggregates (supramolecules). There were 58 papers found by search in Scopus, indicating continuous and active activity in this research area. The macromolecules were sugar-, amino acid-, and nucleic acid-based polymers. The supramolecules were bile salt micelles. The low molecular mass selectors were mainly ionic liquids and complexes with a central ion. A majority of the papers were on the use or preparation of sugar-based macromolecules, e.g., native or derivatised cyclodextrins. Studies to explain chiral recognition of macromolecular and supramolecular chiral selectors were mainly done by molecular modelling and nuclear magnetic resonance spectroscopy. Demonstrations were predominantly on drug analysis for the separation of racemates. Full article
(This article belongs to the Section Analytical Chemistry)
►▼ Show Figures

Figure 1

9 pages, 1785 KiB  
Article
Determination of Biogenic Amines in Seawater Using Capillary Electrophoresis with Capacitively Coupled Contactless Conductivity Detection
by Elbaleeq A. Gubartallah, Ahmad Makahleh, Joselito P. Quirino and Bahruddin Saad
Molecules 2018, 23(5), 1112; https://doi.org/10.3390/molecules23051112 - 8 May 2018
Cited by 28 | Viewed by 4732
Abstract
A rapid and green analytical method based on capillary electrophoresis with capacitively coupled contactless conductivity detection (C4D) for the determination of eight environmental pollutants, the biogenic amines (putrescine, cadaverine, spermidine, spermine, tyramine, 2-phenylamine, histamine and tryptamine), is described. The separation was [...] Read more.
A rapid and green analytical method based on capillary electrophoresis with capacitively coupled contactless conductivity detection (C4D) for the determination of eight environmental pollutants, the biogenic amines (putrescine, cadaverine, spermidine, spermine, tyramine, 2-phenylamine, histamine and tryptamine), is described. The separation was achieved under normal polarity mode at 24 °C and 25 kV with a hydrodynamic injection (50 mbar for 5 s) and using a bare fused-silica capillary (95 cm length × 50 µm i.d.) (detection length of 10.5 cm from the outlet end of the capillary). The optimized background electrolyte consisted of 400 mM malic acid. C4D parameters were set at a fixed amplitude (50 V) and frequency (600 kHz). Under the optimum conditions, the method exhibited good linearity over the range of 1.0–100 µg mL−1 (R2 ≥ 0.981). The limits of detection based on signal to noise (S/N) ratios of 3 and 10 were ≤0.029 µg mL−1. The method was used for the determination of seawater samples that were spiked with biogenic amines. Good recoveries (77–93%) were found. Full article
(This article belongs to the Special Issue Green Analytical Chemistry)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying article 1-50 on page 1 of 1.
Back to TopTop