Search

We pioneered an angle-adjustable photonic crystal fluorescence platform (APC-Fluor) that integrates PCs, an angular resolution spectrometer and a strategically aligned laser source. This configuration, featuring a coaxial rotating swing arm, allows for precise control over the angles of incidence and emission. The presence of photonic crystal microcavities facilitates the dispersion of fluorescent materials and promotes the transition of electrons from the excited state to the lowest vibrational energy level. The optical resonance effect triggered by modulating the alignment of the reflection peaks of the photonic crystals with the emission peaks of the fluorescent materials can significantly enhance the fluorescence intensity. Compared with the single BSA-AuNCs, the optimized fluorescence intensity can be significantly increased by 11.9-fold. The APC-Fluor system showcases rapid and highly sensitive detection capabilities for oxytetracycline (OTC), exhibiting a response across a concentration range from 2 to 1 × 104 nM and achieving a notably low detection limit of 1.03 nM. [ABSTRACT FROM AUTHOR]

In this paper, a simple and easy method of solid phase extraction (SPE) followed by capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection ([C.sup.4]D) is evaluated as a novel approach for the simultaneous determination of acesulfame-K (ACE), sodium saccharin (SAC), and sodium cyclamate (CYC) in foodstuffs without derivatization. To reduce the complex matrix interference resulting from the constituents of samples and enriched targets, porous aromatic frameworks (PAFs) enhanced SPE, a suitable sample pretreatment procedure, was introduced. Several factors affecting extraction efficiency and electrophoretic separation were investigated. Additionally, the interaction mechanisms between the host (PAF-6) and guests (ACE, SAC, and CYC) were studied. Under the optimum conditions, three sulfanilamide artificial sweeteners were baseline separated within 8 min, exhibiting a linear calibration over two orders of magnitude ([R.sup.2] > 0.995). The limits of detection (LOD) and quantification (LOQ) were considered better than those usually obtained by CE with ultraviolet and [C.sup.4]D detection. The proposed SPE--CE--[C.sup.4]D method has been successfully applied to analyse beverage samples and candied fruits with recoveries in the range of 78.89%-92.00%. Key words: porous aromatic frameworks, solid phase extraction, capillary electrophoresis with capacitively coupled contactless conductivity detection, [C.sup.4]D, sulfanilamide artificial sweeteners, foodstuffs. Dans cet article, nous presentons une methode simple et pratique pour l'extraction en phase solide (EPS) suivie d'une electrophorese capillaire (EC) a detection conductimetrique sans contact et a couplage capacitif ([C.sup.4]D) que nous avons evaluee comme nouvelle approche pour le dosage simultane de l'acesulfame-K (ACE), de la saccharine sodique (SAC) et du cyclamate sodique (CYC) dans les produits alimentaires, sans derivation prealable. Afin de reduire les interferences des constituants qui composent la matrice complexe des echantillons, et d'enrichir ceux-ci en analytes, nous avons fait appel a une methode de pretraitement compatible avec ce type d'echantillons, soit l'extraction en phase solide (EPS) amplifiee par des reseaux poreux aromatiques (PAF, acronyme anglais pour Porous Aromatic Frameworks). Nous avons analyse plusieurs facteurs qui influencent l'efficacite de l'extraction et la separation electrophoretique. De plus, nous avons approfondi l'etude des mecanismes d'interaction entre l'hote (PAF-6) et les invites (ACE, SAC, CYC). En conditions optimales, nous avons realise la separation de trois edulcorants artificiels a base de sulfanilamide en 8 minutes a partir des echantillons bruts et nous avons obtenu une calibration lineaire de plus de deux ordres de grandeur ([R.sup.2] > 0,995). Les limites de detection (LD) et de quantification (LQ) se sont revelees inferieures a celles obtenues par EC couplee a une detection ultraviolette ou [C.sup.4]D. Nous avons applique la methode EPS--EC--[C.sup.4]D que nous proposons a l'analyse d'echantillons de boissons et de fruits confits avec des taux de recuperation allant de 78,89 % a 92,00 %. [Traduit par la Redaction] Mots-cles : reseaux poreux aromatiques, extraction en phase solide, electrophorese capillaire a detection conductimetrique sans contact et a couplage capacitif, [C.sup.4]D, edulcorants artificiels a base de sulfanilamide, produits alimentaires., Introduction High-intensity sweeteners can be divided into natural sweeteners and synthetic sweeteners according to their source. (1) Sweeteners have been widely used in foodstuffs since entering the food industry back [...]