Analysis of basic chemicals

Storage tanks on a chemical production plant

On this page, find information on analytical solutions and techniques for the following parameters and processes:

Analysis in accordance with international standards


The chemical industry is highly regulated by a vast body of national and international standards.

We provide the instruments and the know-how that allow you to comply with these standards.

> Find out how you can meet regulatory requirements with Metrohm solutions

Impurities in sulfuric acid

Sulfuric acid is the most-produced chemical in the world. In fact, it is so important that, together with chlorine, it is sometimes used as an indicator of a country’s economic development. Historically named oil of vitriol, it has been known for a long time.

A large portion of the sulfuric acid produced is used in agriculture as a fertilizer. However, the list of uses for sulfuric acid is very extensive, including but by no means limited to:
  • The production of cleaning agents
  • Battery production (as an electrolyte)
  • The pharmaceutical industry
  • The chemical industry
  • The production of resins, paints, inks, dyes, and polymers
For most of these applications, the sulfuric acid must be of sufficient purity. Metrohm offers a series of techniques and applications to determine impurities. Read more below.

Transition metal impurities

Detail of 884 Professional VA instrument for voltammetric measurements
Transition metal impurities can be easily and accurately determined in sulfuric acid with voltammetry. The easy-to-use, easy-maintenance, and robust Multi-Mode Electrode pro used in combination with the voltammetry system allows you to determine:
  • Chromium (with DTPA) using adsorptive stripping voltammetry
  • Molybdenum by polarography in nitric acid solution
  • Nickel and cobalt using adsorptive stripping voltammetry with dimethylglyoxime (DMG) as complexing agent
  • Iron by adsorptive stripping voltammetry with 1-nitroso-2-naphthol (1N2N) as complexing agent

> Learn more about voltammetry

> Learn more about the Multi-Mode Electrode pro


Fluoride, chloride, and nitrate determination with ion chromatography

Detail of ion chromatography system with conductivity detector visible

Ion chromatography is capable of determining fluoride, chloride, and nitrate in concentrated sulfuric acid (between 96 and 98% concentration). The method applied is conductivity detection after sequential suppression.

> Learn more about ion chromatography


Water determination in basic chemicals – solids, liquids, and gases

Overview of LNGs, LPGs, and solids used in basic chemicals manufacturing

When it comes to water determination in chemicals, Karl Fischer titration is the method of choice. In principle, water can be determined in almost any chemical, no matter whether it is solid, liquid, or gaseous.

Here we focus on water determination in salts, liquids, and gases, and particularly on upstream derivatives. Given the countless chemicals for which KF water determination is feasible, it is beyond the scope of this page to provide a complete overview. If, however, you would like to know more, please download our comprehensive Karl Fischer monograph.

> Learn more about water determination in solids

> Learn more about water determination in liquids

> Learn more about water determination in gases


Analysis in the chlor-alkali process

Chlorine ranks no. 7 on the list of the most commonly produced chemical substances. It is the basis for the production of numerous intermediate substances, which, in turn, are important feedstock materials in the petroleum, aluminum, paper and pulp, or pharmaceutical industries. For instance, chlorine is used in the production of a staggering 80% of drugs.

Illustration of the chloralkali process

By far the largest part – about 95% – of the chlorine produced globally is obtained via the chlor-alkali process. In this process, chlorine and caustic soda are produced via electrolysis of sodium chloride brine. Caustic soda is another crucial basic chemical which is used in many chemical processes. Three electrolysis methods are applied for the chlor-alkali process, using either a diaphragm or a mercury or membrane cell.

For the process to be as efficient as possible, the brine has to be free of impurities. This makes chemical analysis necessary.

Read below what we have to offer for analyzing sodium chloride brine.

Ions in brine and alkali hydroxides with ion chromatography

Chromatogram of ions in brine

Ion chromatography is ideally suited for determining cations (lithium, sodium, ammonium, potassium, calcium, magnesium, and strontium) and anions (chlorate and sulfate) in sodium chloride brine and alkali hydroxides. The detection method applied is conductivity detection.

> Learn more about ion chromatography


Titration: One method for many parameters

Two heaps of salt

Titration is a highly versatile method that makes a multitude of analyses possible. Metrohm has developed applications for the potentiometric, photometric, and thermometric titration of analytes in brine, e.g., sodium, halides, sulfate, or calcium.

> Learn more about potentiometric titration

> Learn more about thermometric titration

> Learn more about photometric titration


Iodide in brine with voltammetry

Voltammogramm of salt in brine and standard addition curve

In chlorine production, the most commonly applied electrolysis technique is the membrane process. This process requires high-purity brine in order to run efficiently. One of the main impurities that need to be monitored is iodide. The reason is that iodide readily oxidizes at the anode in the electrolysis cell. The resulting oxidation products precipitate inside the ion-exchange membrane and thus reduce the membrane's service life.

Voltammetry is predestined for iodide determination in brine. The method is straightforward and inexpensive and yields highly precise results.

> Learn more about voltammetry


Process solutions for saturated brines

Urea: The birth of modern organic chemistry

To chemists, urea is a special substance. It was the first organic compound produced from the inorganic materials ammonium hydroxide and lead cyanate. The synthesis of urea put an end to the then popular idea of vitalism, according to which only living organisms – by virtue of the so-called vital force – were capable of producing organic compounds. This synthesis, discovered by Friedrich Wöhler in 1828, was the birth of organic chemistry.

Friedrich Wöhler, discoverer of urea synthesis

With global production in excess of 150 million tons per year, urea belongs to the world’s top 10 organic compounds produced. The bulk of this is used as a nitrogen fertilizer in agriculture, where it plays a key role in producing food for the world’s growing population.

However, urea is also used in a vast number of other industries, e.g.:

  • In dermatological products in the cosmetics and pharmaceutical industries.
  • As an additive that reduces pollutants in exhaust gases in the automotive industry (diesel exhaust fluid, DEF, or AdBlue).
  • As a raw material in the production of melamine and urea-formaldehyde resins in the polymer industry.

Determining urea

Ball-and-stick model of a urea molecule, image created by Jynto, via Wikimedia Commons

Urea can be determined accurately by titration with thermometric detection. In this application, urea is dissolved in glacial acetic acid and titrated with trifluoromethanesulfonic acid using isobutyl vinyl ether as a thermometric endpoint indicator. This method can also be fully automated.

> Learn more about thermometric titration

> Learn more about automation


Determining impurities in urea

Automated ion chromatography system with extensiom module and sample processor
Analytical techniques are required to determine the purity of urea. Ion chromatography is an excellent technique for impurity analysis. Using anion chromatography with chemical suppression and conductivity detection, you can analyze traces of impurities reliably and accurately, e.g., chloride, cyanate, nitrate, and sulfate.

In addition, in urea-based fertilizers, ion chromatography can determine residual ammonium and guanidinium.

> Learn more about Metrohm ion chromatography



Evonik Goldschmidt GmbH

"I have been working for 24 years with Metrohm and they have never ever let me down."

Christian Goetz, deputy manager of "Silicons" QC laboratory at Evonik Goldschmidt GmbH


"We have chosen Metrohm because these systems are rugged, versatile, and easy to operate."

Daniel Matuschka, QC lab technician, Sigma-Aldrich, Steinheim (Germany)

Bernd Kraft GmbH

"We decided to go with Metrohm due to the exceptional application support we get, the robust suppressor and the modular design of the system."

Dieter Bossmann, Laboratory Manager, Bernd Kraft, Germany