Dispersive liquid-liquid microextraction of parabens from pharmaceuticals and personal care products prior to their determination using HPLC-DAD

Dispersive liquid-liquid microextraction followed by a back-extraction step was combined with HPLC-DAD for the determination of four parabens (i.e. methyl-, ethyl-, propyl-, and butylparaben). Optimum extraction conditions were found as follows: 225 mu L of chloroform, 0.75 mL of ethanol, 7.5 mL of aqueous solution and within an extraction time of 15 s. Back-extraction into 100 mu L of 50 mM sodium hydroxide solution within 20 s resulted in a reversed-phase HPLC-compatible extract. The analytes were separated at 20 degrees C using methanol (A) and water (B), 40:60 (A:B, v/v) as the mobile phase, a flow rate of 1.0 mL min(-1) and an injection volume of 20 mu L. DAD was set at 258 nm to monitor the analytes. Limits of detection and quantitation were as low as 0.1 and 0.3 mu g mL(-1), respectively. Coefficients of determination (R-2) were higher than 0.9950 and percentage relative recoveries were found in the range of 86.5-114.5\% for the four parabens from pharmaceuticals and personal care products

Polyethyleneimine brushes effectively inhibit encrustation on polyurethane ureteral stents both in dynamic bioreactor and in vivo

ERTAS, NUSRET/0000-0002-9770-3292WOS: 000390967200135PubMed: 27987673Polyurethane (PU) ureteral stents have been widely used as biomedical devices to aid the flow of the urine. Due to the biofilm formation and encrustation complications it has been hindered their long term clinical usage. To overcome these complications, in this study, cationic polyethyleneimine (PEI) brushes grafted on PU stents and their performances were tested both in a dynamic biofilm reactor system (in vitro) and in a rat model (in vivo). Thus, we hypothesized that PEI brushes inhibit bacterial adhesion owing to the dynamic motion of brushes in liquid environment. In addition, cationic structure of PEI disrupts the membrane and so kills the bacteria on time of contact. Cationic PEI brushes decreased the biofilm formation up to 2 orders of magnitude and approximately 50% of encrustation amount in respect to unmodified PU, in vitro. In addition, according to Atomic Absorption Spectroscopy (AAS) results, approximately 90% of encrustation was inhibited on in vivo animal models. Decrease in encrustation was clearly observed on the stents obtained from rat model, by Scanning Electron Microscopy (SEM). Also, histological evaluations showed that; PEI brush grafting decreased host tissue inflammation in close relation to decrease in biofilm formation and encrustation. As a results; dual effect of anti adhesive and contact-killing antibacterial strategy showed high efficiency on PEI brushes grafted PU stents both in vitro and in vivo. (C) 2016 Elsevier B.V. All rights reserved.Scientific and Technological Research Council Turkey of (TUBITAK) [112M293]This study is financially supported by The Scientific and Technological Research Council Turkey of (TUBITAK) (Grant no: 112M293)

Rapid Detection of Acrylamide in Food Using Mn-Doped ZnS Quantum Dots as a Room Temperature Phosphorescent Probe (vol 11, pg 1367, 2018)

The original version of this article unfortunately contained mistakes. The sentence ``ACR was determined in all samples in the range of 24.3 to 453.2 g kg(-1).{''} should read ``ACR was determined in all samples in the range of 24.3 to 453.2 mu g kg(-1).{''} In Table 2 header, it should be ``Sample value (mu g kg(-1)){''}

Multiplex enumeration ofEscherichia coliandSalmonella enteritidisin a passive capillary microfluidic chip

Multiplex detection and quantification of bacteria in water by using portable devices are particularly essential in low and middle-income countries where access to clean drinking water is limited. Addressing this crucial problem, we report a highly sensitive immunoassay sensor system utilizing the fluorescence technique with magnetic nanoparticles (MNPs) to separate target bacteria and two different types of quantum dots (CdTe and Ni doped CdTe QDs) incorporated into a passive microfluidic chip to transport and to form sandwich complexes for the detection of two target bacteria, namelyEscherichia coli(E. coli) andSalmonella enteritidis(S. enteritidis) in less than 60 min. The assay is carried out on a capillary driven microfluidic chip that can be operated by merely pipetting the samples and reagents, and fluorescence measurements are done by using a handheld fluorescence spectrophotometer, which renders the system portable. The linear range of the method was found to be 10(1)to 10(5)cfu mL(-1)for bothE. coliandS. enteritidis. The limit of detection (LOD) was calculated to be 5 and 3 cfu mL(-1)forE. coliandS. enteritidis, respectively. The selectivity of the method was examined by testingEnterobacter dissolvens(E. dissolvens) andStaphylococcus aureus(S. aureus) samples, and no significant interference was observed. The method was also demonstrated to detect bacteria in tap water and lake water samples spiked with target bacteria