Comparison of methods for the synthesis of silver nanoparticles stabilized in a solid polymethacrylate matrix.

Silver nanoparticles were synthesized inside the small plates of transparent polymer medium by reduction of silver cations. The difference in morphology and sizes of nanoparticles synthesized by chemical, photochemical and thermal reduction was revealed, which depends both on the component ratio of the mixture and on the reduction time for the specific component ratio The polymethacrylate matrix itself acts as the stabilizing agent. A colorimetric sensor based on polymethacrylate matrix and silver nanoparticles was developed for the detection of hydrogen peroxide.

Solid phase colorimetric determination of iodine in food grade salt using polymethacrylate matrix.

A novel colorimetric sensor has been proposed for sensitive and accurate detection of iodine forms using polymethacrylate matrix, which also has the outlook for use with samples without pre-treatment and is suitable to fit in a portable instrument for in situ iodine analysis. This determination method is based on interaction of polymethacrylate matrix with iodine forms followed by measurement of absorbance at 370 nm. The principle of this colorimetric sensor is not ordinary colorimetry, but a new colorimetric strategy that combines solid phase extraction and spectrophotometric determination of a target substance following completion of the color change processes.

Solid phase-enhanced photothermal lensing with mesoporous polymethacrylate matrices for optical-sensing chemical analysis.

Procedures for the photothermal lens determination of metals and organic compounds, on the basis of solid-phase mesoporous optical-sensing materials (polymethacrylate [PMA]) matrices with immobilized reagents, were developed. These procedures combine (i) selective and efficient preconcentration of trace substances to be analyzed in specially designed and synthesized transparent mesoporous PMA plates; (ii) sensitive determination with the reliable and traceable photometric reactions previously developed for classical spectrophotometry; and (iii) the sensitivity enhancement of photothermal lens detection in polymers, which provides at least a ten-fold increase in sensitivity compared with solutions due to polymer thermo-optical properties (solid phase-enhanced thermal lensing). It is shown that the overall sensitivity of photothermal lens measurements in PMA matrices is two orders higher than photometric absorbance measurements for the same excitation source power, which is in good agreement with the expected theoretical sensitivity.