Optimization of an ultrasound-assisted alcohol-based deep eutectic solvent dispersive liquid-phase microextraction for separation and preconcentration of quercetin in wine and food samples with response surface methodology.

We optimized ultrasound-assisted alcohol-based deep eutectic solvent dispersive liquid-phase microextraction for separation and preconcentration of quercetin in wine and food samples by experimental design based on central composite design. Five different alcohol-based deep eutectic solvents were prepared and tested for quercetin extraction. The effect of important parameters and matrix components were optimized. After optimization, the determination of quercetin was performed at 385 nm using spectrophotometry. Analytical data such as detection limit, working range and preconcentration factor were found as 6.1 µg/L, 20-850 µg/L, and 120, respectively. The selectivity of the optimized extraction conditions for quercetin was investigated in the presence of different matrices. The validation of the method was investigated by reproducibility, repeatability and recovery studies, as well as by comparing the analytical results obtained from real samples with the reference method. Lastly, the recommended procedure was successfully applied for the extraction and quantification of quercetin in wine and food samples.

Towards green analysis of curcumin from tea, honey and spices: Extraction by deep eutectic solvent assisted emulsification liquid-liquid microextraction method based on response surface design.

A fast, cheap and green analytical method was developed for the determination and extraction of curcumin in tea, honey, and spices using deep eutectic solvent-assisted emulsification liquid-liquid micro-extraction (DES-ELLME) coupled to UV-VIS spectrophotometry. Quantitative extraction of curcumin from the sample was obtained by the DES, which was prepared by mixing choline chloride and maltose in a 1:3 molar ratio. Response surface design was used for the optimisation of significant experimental parameters including sample pH, amount of extraction solvent, amount of emulsifier solvent and vortex time. The optimum conditions obtained were pH 4.25, 762.5 µL of DES, 107.5 mL of tetrahydrofuran and 3.4 min vortex time, while keeping centrifugation speed fixed at 4000 rpm, 5 min. Under the extraction conditions obtained, analytical features such as calibration equation, limit of detection, enrichment factor, and linearity were Abs = 6.5 × 10-4 [Curcumin, ng mL-1]-1.2 × 10-5, 0.1 ng mL-1, 114 and 0.4-120 ng mL-1, respectively. Moreover, the repeatability and reproducibility of the DES-ELLME method, expressed as relative standard deviation (RSDs%), varied in the ranges of 1.4-3.0% and 2.0-4.3%, respectively. Finally, the proposed method was successfully applied to the extraction and determination of curcumin from prepared samples. The relative mean recovery ranged from 92.3% to 104.4%.

Development of a chemometric-assisted deep eutectic solvent-based microextraction procedure for extraction of caffeine in foods and beverages.

In this research article, a novel and green deep eutectic solvent-based microextraction (DES-ME) procedure based on chemometric-assisted (CA) optimization was developed for the extraction of caffeine in foods and beverages prior to its spectrophotometric determination. Ultrasound was used to accelerate the extraction of caffeine. Deep eutectic solvents (DES), prepared in an ultrasonic bath at 20-60 min for 60-80°C, were used as extraction solvents. The important experimental variables (pH, DES amount, temperature, sonication time and metal concentration) were modelled and optimized using response surface methodology (RSM) based on central composite design (CCD). Under the optimum conditions, the proposed method allowed the determination of caffeine with limits of detection (LOD, 3sblank/m) and quantification (LOQ, 3sblank/m) of 7.5 and 25.0 µg L-1, respectively. For 40 µg L-1 and 100 µg L-1 of caffeine (n = 5), relative standard deviations (RSDs%) and recoveries% were 1.2-1.6% and 96.7-98.2%, respectively. Validation studies (accuracy, precision, trueness, reliability and selectivity) of the method were performed before the analysis of real samples. The results showed that the combination of the CCD with the DES-ME can be considered as a new perspective for the extraction and determination of caffeine in foods and beverages.

[Is there any relation between type 1 halitosis and oral candida colonisation?] / Tip 1 agiz kokusu ile agizda kandida kolonizasyonu arasinda iliski var mi?

Pathologic halitosis has been classified into 5 types: oral, airway, gastroesophageal, blood-borne and subjective, respectively. Type 1 (oral) halitosis mostly takes origin from anaerobic bacterial activities on oral surfaces. The role of anaerobic bacterial activities is clearly demonstrated, but despite the large number of anectodal claims, the role of Candida in patients with halitosis has not been adequately investigated. The aim of this study was to confirm the relationship between Candida and halitosis. A total of 136 subjects were enrolled and divided into two groups. The study group comprised of 69 patients with halitosis who had over 0.7 ppm H2S concentration in their oral cavity and the control group comprised of 67 healthly subjects. Self assesment scores for halitosis, Candida colony counts in saliva samples, oral NH3, SO2, H2S, H2 and volatile organic gas concentrations were recorded. H2S producing capacity of subjects was quantified by applying cysteine challenge test. Candida samples were taken from the mouths of the patients with and without halitosis, and Candida albicans isolates were inoculated into broth medium. After 3 days of incubation at 37oC, gas concentrations of the headspace of the flasks were read by a portable multigas detector. The rate of Candida positivity was 44.9% in the study group while it was 46.3% in the control group. There was no statistical significant difference between the groups according to the Candida growth (p= 0.561). The oral gas concentrations were comparable in both groups (p< 0.05). Oral H2S concentration increased 9.65 fold with 20 mM cysteine rinse in patients with halitosis while it was increased 5.8 fold in controls. Self assesment for halitosis were well correlated with clinical signs (p= 0.001, r= 0.8). Concentrations of hidrogen and organic gases were found to be increased in all Candida culture media. In this study, no relationship between the presence of Candida and oral halitosis was detected. As a result, there is no need for diets similar to Candida diet in the treatment of halitosis. On the other hand, cysteine challenge can be a useful diagnostic tool. In addition, portable gas detectors can be used as a convenient and practical halitometer to quantify halitosis.