Applications

The coupling of highly efficient ion chromatography (IC) to multi-dimensional detectors such as a mass spectrometer (MS) or an inductively coupled plasma mass spectrometer (ICP/MS) significantly increases sensitivity while simultaneously reducing possible matrix interference to the absolute minimum. By means of IC/MS several oxyhalides such as bromate and perchlorate can be detected in the sub-ppb range. Additionally, organic acids can be precisely quantified through mass-based determination even in the presence of high salt matrices. By means of IC-ICP/MS different valence states of the potentially hazardous chromium, arsenic and selenium in the form of inorganic and organic species can be sensitively and unambiguously identified in one single run.

Metal precipitation and cyanide recovery in the SART process (sulfidization, acidification, recycling, thickening) depend to a great extent on the sulfide concentration. Among the flow injection analysis methods coupled to wet-chemical analyzers, the combination of a gas diffusion cell with an ion chromatograph (IC) plus subsequent direct spectrophotometric detection has proven to be one of the most convenient methods of sulfide analysis.This paper deals with the determination of sulfide anions via the coupling of a gas diffusion cell to an IC with subsequent spectrophotometric detection.

This poster presents a highly reproducible procedure for the determination of the sodium contribution of acid-extractable organic species in Bayer process liquor. The precision of the method is estimated to be 0.2% RSD.

This poster presents a straightforward ion chromatographic determination of HF, HNO3, short-chain organic acids and H2SiF6 in etching bath samples. Standard ions such as fluoride, nitrate, acetate and sulfate are determined via suppressed conductivity detection while dissolved silicate is spectrophotometrically detected in the same run after downstream post-column reaction (PCR) as molybdosilicic acid. Analytical results of several commercial HF-HNO3-H2SiF6 mixtures obtained by ion chromatography (IC) and titration showed good agreement, which confirms the applicability of the presented «dual» detection IC method for controlling the composition of acidic texturing baths.

Thermometric titration can solve application problems that potentiometry cannot solve at all, or at least not satisfactorily.

An automatic titration method is described using biamperometric endpoint indication for the determination of antimony in antimony-alloyed cable lead (approx. 1% Sb). A 0.01 mol/L KBrO3 solution is used as the titrant.

Zinc, such as that occurring as a constituent of light alloys, can be determined by precipitation titration with potentiometric endpoint indication. The determination of zinc in the presence of cadmium is also possible.2 K4[Fe(CN)6] + 3 ZnCl2 → K2Zn3[Fe(CN)6]2 + 6 KCl

A potentiometric method for the determination of nickel in gold and silver electroplating baths is described. The titration is carried out with KCN. Gold and silver are removed before titration by a reduction process. It is also possible to determine nickel in steel alloys, etc. (see the literature reference).Ni2+ + 4 KCN + 2NH4+ → (NH4)2[Ni(CN)4] + 4 K+

Two methods are described for the determination of chromium: a biamperometric titration and a polarographic analysis.

Silver is an important metal not only in jewelry and silverware but also in electrical conductors and contacts. The knowledge of the exact silver content in fine silver and silver alloys ensures that quality standards for jewelry and silverware are met. As for the plating industry, the knowledge of the amount of silver in silver plating baths helps to run the bath efficiently.While X-ray fluorescence (XRF) is a fast alternative to determine the silver content in fine silver and silver alloys, it can only determine the silver content of the outermost sections of the metal. In contrast, titration offers a more comprehensive solution considering the whole sample, thus preventing fraud by thick plating.This application bulletin describes the potentiometric determination of silver in fine silver and silver alloys accordingto EN ISO 11427, ISO 13756, GB/T 17823, and GB/T 18996 as well as in silver plating baths by a titration with potassium bromide or potassium chloride, respectively

This Bulletin describes potentiometric titration methods for checking sulfuric acid and chromic acid anodizing baths. In addition to the main components aluminum, sulfuric acid, and chromic acid, chloride, oxalic acid, and sulfate are determined.

Potentiometric titration methods for the analysis of acid and alkaline tin plating baths are presented. The following methods are described: tin(II) / tin(IV) / total tin, free fluoroboric acid, or free sulfuric acid, chloride in acidic tin baths, free hydroxide, and carbonate in alkaline tin baths.

A method is described in this Bulletin that allows molybdenum to be determined in steel and other materials containing a high iron concentration. Mo(VI) is determined at the dropping mercury electrode by catalytic polarography. The determination limit is approx. 10 μg/L Mo(VI).

In most electrolytes the peak potentials of lead and tin are so close together, that a voltammetric determination is impossible. Difficulties occur especially if one of the metals is present in excess.Method 1 describes the determination of Pb and Sn. Anodic stripping voltammetry (ASV) is used under addition of cetyltrimethylammonium bromide. This method is used when:• one is mainly interested in Pb• Pb is in excess• Sn/Pb ratio is not higher than 200:1According to method 1, Sn and Pb can be determined simultaneously if the difference in the concentrations is not too high and Cd is absent.Method 2 is applied when traces of Sn and Pb are found or interfering TI and/or Cd ions are present. This method also uses DPASV in an oxalate buffer with methylene blue addition.

Mixtures of aluminum and magnesium ions can be analyzed automatically using potentiometric titration. The excess DCTA is back-titrated with copper(II) sulfate solution after the addition of 1,2-diaminocyclohexanetetraacetic acid (DCTA) and complex formation. The ion-selective copper electrode is used here as the indicator electrode. First, the aluminum is determined in acidic solution and then the magnesium in alkali solution.

Thiourea forms highly insoluble compounds with mercury. The resulting anodic waves are used for the polarographic determination of thiourea. For the analysis of very small quantities (µg/L), cathodic stripping voltammetry (CSV) is used. Differential Pulse measuring mode is used in both cases.

The determination of the total causticizer, sodium carbonate and aluminum oxide contents in (Bayer) process liquors can be accomplished with high precision and speed by using the 859 Titrotherm in a thermometric acid-base titration. A complete titration takes approximately 5 minutes.The procedure is an automated adaptation of the traditional Watts-Utley method, and is similar to the VanDalen-Ward thermometric titration method, but with the added advantage that the analysis can also be performed for the carbonate content of the liquor.

Eco Titrators provide the capability to send PC/LIMS reports directly to a PC. This feature is mainly used to transfer data to an external LIMS system or to simply store the data in a digitally on the PC. Additionally, it is possible to control the Eco Titrator by RS232 commands if the connection is set up according to the procedure described below.The data transfer from the Eco Titrator to a PC can be done by a software- or a hardware-based option. Additional accessories are needed for the hardware-based option whereas for the software-based option two additional softwares must be installed. Both solutions are described in this document.

This Application Bulletin contains installation instructions for the MVA-24 CVS setup used to measure suppressors, brighteners, and levelers in plating solutions.

Determination of calcium and magnesium in rock extracts using cation chromatography with direct conductivity detection.

In order to extract aluminum from bauxite, the aluminum ore is exposed with a caustic soda solution under pressure in the temperature range of 150 to 200 °C. Dilution and pH value setting are implemented by the addition of 170 mmol/L citric acid prior to calcium determination with ion chromatography in the Bayer caustic soda. Doing so establishes a pH value of 4.5 and prevents precipitation of aluminum hydroxide. The IC separation takes place on the Metrosep C 4 - 150/4.0 column with a citric acid eluent.

Copper concentrate is an important raw material for copper mills. The concentrate is often contaminated with corrosive fluorine, which is why the fluorine concentration must be checked at regular intervals. A convenient and reliable determination method is Combustion IC in combination with sacrificing vial technology. The sample is placed inside the quartz combustion pipe in a horizontally positioned quartz vial, both ends of which are sealed with glass wool. During combustion, the quartz-destroying components (e.g., fluoride, alkali and earth alkali metals) that are released are captured by the quartz vial and the quartz wool, ensuring that they are thus unable to reach the quartz combustion pipe at all.Keyword: pyrohydrolysis

Iron ore is an important resource for steel production. Its natural content of halogens is a quality characteristic due to the corrosiveness of the respective halogenides. Combustion IC applying the sacrificial vial technology is used for the analysis of fluorine and chlorine in ore. WO3 usually is added to improve the release of SO2 and therefore sulfur recovery. In this application, it also significantly improves the recovery of fluoride.

Corrosion refers to a process that involves deterioration or degradation of metal. The most common example of corrosion is the formation of rust on steel. Most corrosion phenomena are of electrochemical nature and consist of at least two reactions on the surface of the corroding metal.

Electrochemical methods provide an alternative to traditional methods used to determine the rate of corrosion. For example, corrosion rates, the rates at which a specimen corrodes, can be calculated from simple electrochemical measurements like a linear sweep voltammetry (LSV).

In real life, often, corrosion is a result of several reactions and it is not possible to determine a priori the reaction mechanism. In such cases, the polarization resistance can be used to determine the resistance of the metal under investigation against corrosion.

Electrochemical impedance spectroscopy or EIS has been used effectively to measure the polarization resistance for corrosion systems and for the determination of corrosion mechanisms.

This Application Note is based on the ASTM standard G150, developed to test the resistance of stainless steel, and otheralloys related to stainless steel, on pitting formation at elevated temperature. This is achieved by determining the potential-independent critical pitting temperature (CPT), defined as the lowest temperature at which pitting evolution occurs. The CPT experiment consists of applying a potential to the specimen while the cell temperature is raised and recording the current.

In this Application Note, stepwise dissolution measurement (SDM) is applied to aluminum samples coated with different materials, in order to gain insights in corrosion protection. The combination of the Autolab PGSTAT204 with the 1 L Autolab corrosion cell and the NOVA software provides the suitable setup to perform SDM and other corrosion experiments.

In this Application Note, EIS is applied on three coated aluminium samples, before and after the stepwise dissolution measurement (SDM). This technique has been reviewed in the Application Note AN-COR-08.

Corrosion of metals is a problem seriously affecting not only many industrial sectors, but also private life, resulting in enormous costs. In this application note, the results gained during electrochemical corrosion studies on different metals are compared to literature data.

Tafel analysis is an important electrochemical technique used to understand reaction kinetics. By studying the Tafel slope, it reveals the rate-determining steps in electrode reactions, aiding fields like corrosion and fuel cell research. This method helps industries optimize processes and improve device performance by tailoring materials and conditions for greater efficiency.

With the advent of electric automobiles, the demand for lithium batteries and with it the demand for lithium material will increase sharply. Brine lakes and hard silicate minerals are numbered among the most important sources of lithium. This Application Note addresses cation determination in seepage water from lithium minerals. Alkali and earth alkali metals are separated in the lithium digestions on the Metrosep C Supp 1 - 250/4.0 column, with subsequent conductivity detection after sequential suppression.

In this Application Note, hydrogen permeation experiments are conducted following the procedure described in the ASTM standard G148.

The Devanathan-Stachurski cell (or «H cell») is successfully used to evaluate the permeation of hydrogen through sheets or membranes. As small amounts of hydrogen pass through the sheet or membrane, a very sensitive potentiostat is required for its detection. A study of the hydrogen permeation properties of different iron sheets is discussed in this Application Note while taking the instrumental requirements into account.

This Application Note explains manual and automated iR drop correction with electrochemical impedance spectroscopy and cautions against using less accurate methods.

Electrochemical impedance spectroscopy (EIS) is a widely used multidisciplinary technique for characterizing the behavior of complex electrochemical systems. EIS is employed in the study of a range of complex systems including batteries, catalysis, and corrosion processes. This Application Note focuses on the basic principles of EIS measurements.

A typical electrochemical impedance spectroscopy (EIS) experimental setup consists of an electrochemical cell, a potentiostat/galvanostat, and a frequency response analyzer (FRA). This Application Note introduces common EIS experimental setups as well as details of the main experimental parameters.

Here, the most common circuit elements for EIS are introduced which may be assembled in different configurations to obtain equivalent circuits used for data analysis.

Explore how to construct simple and complex equivalent circuit models for fitting EIS data in this Application Note. Nyquist plots are shown for each example.

This Application Note explains how fluoride determination in acid etching baths can be performed with thermometric titration.

Determination of cuprous ions in the presence of ferrous ions in electrochemical copper leaching solutions.

Determination of water in moist particulate solids such as cobalt oxyhydroxide.

Determination of free acid in solutions containing metal ions, particularly Fe(III).

Determination of free acid in copper refining solutions.

Determination of nickel in the absence of cobalt and other interferences.

This Application Note describes a method for the determination of causticizer, carbonate and aluminum oxide in used Bayer process liquors. The method is based on processes that were developed by Watts-Utley and VanDalen-Ward.

Determination of total basicity of extractable organic compounds of acidic character in Bayer process refinery liquors.

Determination of phosphate content in an acid etching bath.

Determination of nickel in solution by titration with standard disodium dimethylglyoximate.