Evaluation of Rh, Ir, Ru, W–Rh, W–Ir and W–Ru as permanent modifiers for the determination of lead in ashes, coals, sediments, sludges, soils, and freshwaters by electrothermal atomic absorption spectrometry

Application of Brazilian-pine fruit coat as a biosorbent to removal of Cr(VI) from aqueous solution—Kinetics and equilibrium study

“…All solutions were stored in high-density polyethylene bottles, as already recommended [27]. Plastic and glassware materials were cleaned by soaking in 10% (v/v) HNO 3 for 24 h [28], rinsing five times with de-ionized water and dried and stored in a flowhood.…”

Determination of Cadmium, Chromium, Copper and Lead in Sediments and Soil Samples by Electrothermal Atomic Absorption Spectrometry Using Zirconium Containing Chemical Modifiers

“…Volynsky 13 gave a critical review on the investigation of the mechanism of chemical modifiers. Different chemical modifiers, such as PdMg(NO3)2, 10,14 Pd and Eu-Pd, 7 Ir, 15,16 Zr, 16,17 Zr-Ir coating 18 and EDTA, 19 were added to aqueous standards and samples by using platforms inserted into pyrolytically-coated graphite tubes. These additions and a Zeeman effect background corrector 7,8,18 have been recommended to overcome the background absorption and interference effects in the sample matrix, and to improve the precision and accuracy.…”

“…21 The Zr, Ir and Zr + Ir coatings as permanent modifiers onto platform were not used, since atomization temperatures of Cr and Cu were higher than 2200˚C and loss of modifier mass occured above this temperature. 9,15 …”

“…Decomposition of samples was performed in a Milestone Ethos Sel microwave oven according to the following procedures described in previous works 9,15,22,23 in three replicates. A portion of each sample (0.10 -0.30 g) was accurately weighed into a Teflon digestion vessel, then 2.0 ml concentrated HNO3, 1.0 ml concentrated HClO4 and 1.0 ml HF were subsequently added to the vessel, with a gentle swirl of the acid mixture.…”

Equilibrium study of single and binary adsorption of lead and mercury on bentonite-alginate composite: Experiments and application of two theoretical approaches

“…After the equilibrium time (6 h), the adsorbent was removed from the solution by centrifugation, and the equilibrium concentration of the metal was analyzed using an atomic absorption spectrophotometer (Shimadzu). The amount of metal adsorbed at equilibrium condition (q e ) was calculated by the following equation [35,36]:…”