Smartphone-based colorimetric determination of fluoride anions using polymethacrylate optode.

We developed a new transparent polymer optode based on polymethacrylate with Zr(IV) and alizarin red complex immobilized into it for digital colorimetric and solid-phase spectrophotometric determination of fluoride anions. The matrix changes its colour from purple to yellow after it contacts fluoride anion. We developed a processing algorithm for coloured images which helps calculate mean value for the RGB colour-coordinate system in a selected optode image and translates it into a fluoride concentration value. The analytical signal of the suggested method has a linearity range of 0.1-30 mg⋅L-1 with the detection limit 0.03 mg⋅L-1. Compared to other methods, the modified polymethacrylate matrix is actually a ready-to-use colorimetric system offering rapid results for drinking water quality control.

Determination of antioxidant capacity of medicinal tinctures using cuprac method involving Cu(II) neocuproine immobilized into polymethacrylate matrix.

This work suggests using Cu(II) - neocuproine redox system immobilized into transparent polymethacrylate matrix for assessment of antioxidant capacity using CUPRAC method. The method we developed makes it possible to quantify the content of the antioxidants in the concentration range of 5.9 × 10-8-9.1 × 10-5 M. The sensor was tolerant to pH variations and painting, and used for the antioxidant capacity determination values of some commercial medicinal tinctures without pretreatment.

Colorimetric determination of food colourants using solid phase extraction into polymethacrylate matrix.

This paper describes a simple colorimetric method for determination of Brilliant Blue, Sunset Yellow, Ponceau 4R and Tartrazine using transparent polymer optode. The method provided acceptable linear ranges 0.01-3.0 mg L-1 with correlation coefficients higher than 0.995 under the optimal conditions. Commercial beverages and juices containing different amounts of food dyes were analyzed and the results were compared to those obtained by HPLC.

Colorimetric and fluorescent sensing of rhodamine using polymethacrylate matrix.

This is a description of the tracer analysis method involving colorimetric and fluorescent measurements based on solid phase extraction of rhodamine into transparent polymethacrylate matrix. Concentration of rhodamine in PMM is measured as spectrophotometric absorption level at 535 nm and fluorescence at 554 nm. The calibration graphs are linear within the ranges 0.02-0.10 mg∙L-1 and 0.002-0.06 mg∙L-1 and detection limits 0.014 mg∙L-1 and 0.0005 mg∙L-1 are calculated for colorimetric and fluorescent measurements, respectively. The method has been successfully used for determination of rhodamine in groundwater.

[Prevention of wound complications and recurrences in large ventral hernias]. / Profilaktika ranevykh oslozhnenii i retsidivov pri bol'shikh ventral'nykh gryzhakh.

An experience with prophylactics of wound complications and recurrences in treatment of 92 patients with great ventral hernias is analyzed. The incidence of wound complications was decreased from 34% to 9.5%, recurrences from 14% to 2.4%.