Optical and electrochemical sol-gel sensors for inorganic species

Abstract

The use of sol-gels as a sensing matrix for the development of unique sensing strategies is discussed. Sol-gels offer almost limitless possibilities for sensing substrates due to the variety of physical properties that can be obtained by altering a number of discussed fabrication conditions and techniques. By careful consideration of the sensing requirements, novel detection methods have been developed for a variety of analytes and applications. Here, sol-gels have been used to monitor pH at the extreme ends of the scale ([H + ] = 1-11 M and [OH − ] = 1-10 M) and in mixed solvent/solute systems using dual sensing approaches. The use of ligand-grafted sol-gel monoliths for optical determination of metal ion species is also discussed. The electrochemical determination of Cr(Ⅵ) by electrodeposited sol-gel modified electrodes is also presented.sol-gel, organofunctional, acid, base, metal ions

Optimization of Dry Ashing of Whole Blood Samples for Trace Metal Analysis

“…Arguments such as possible sample loss, reaction with the container's surface, and incomplete ashing have been presented [23,28]. Yet many still regard dry ashing as a viable practice provided care is taken in the process [9][10][11][12]14,21,22,29].…”

“…Intermittent stirring allowed even ashing and monitoring of the sample. Ashing was determined complete when the sample was a rust red-brown color, typical for iron oxides, and no black substance, indicating carbon, remained [21,22]. Total ashing time was dependent on the volume of sample in the evaporating dish.…”

“…After 90 min, the temperature of the flame was increased to 450˚C and the sample was heated continuously for several hours. Ashing was determined complete when the sample was a rust red-brown color, typical for iron oxides, and no black substance, indicating carbon, remained [21,22].…”

“…Ashing procedures have long been used to pretreat complex samples such as biological tissues and fluids prior to elemental analysis [4][5][6][7][8][9][10][11][12][13]. Dry ashing in particular has been a standard in the analysis of many biological samples, and it has been used as a benchmark in the development of new analyticcal methods [9][10][11][12][14][15][16][17][18][19][20][21][22][23] with many citations in this year alone [15][16][17][18][19][20]. Other techniques have been used as well but these are either expensive [4,6] or more ideal for identifying specific elements [5,8,13,24].…”

Flower-like self-assembly of gold nanoparticles for highly sensitive electrochemical detection of chromium(VI)

“…A number of sensitive techniques have been employed, such as atomic absorption spectrophotometry [5], plasma mass spectrometry [6], spectrofluorimetry [7], spectrophotometry [8], and chemiluminescence [9], but each of these processes is time consuming and necessitates expensive equipments. Various sensor systems have also been reported [10–16]. Most of these systems, however, have either limitations in sensitivity, simplicity or the high cost of equipments as well.…”