Physical properties

The laboratory is equipped with both field and lab equipment to study physical (soil) properties. Some examples include a penetrologger to study the bearing capacity and compaction of soils, an easy to use automated setup to measure hydraulic conductivity in the laboratory, a wet sieving apparatus to study aggregate stability and two different particle size analysers, one using X-ray absorption and sedimentation and the other laser diffraction.

Microbial activity

The RESPICOND system is a temperature controlled respirometer with which it is possible to measure respiration rate for up to 95 samples simultaneously over extended periods of time. Evolution of CO2 is measured by capturing it in KOH and monitoring the change in conductance.

Our Gas Chromatograph is used for the analyses of permanent gasses: carbon dioxide, nitrous oxide and methane in gaseous samples originating from field-sites or lab incubation experiments and for the measurement of acetylene and ethylene in incubated samples.

Segmented flow analyzer

With a segmented flow analyzer (SFA) nutrients are routinely measured in aqueous samples, such as surface water and seawater, and in soil extracts. The two SFA machines available (produced by Skalar, Breda, the Netherlands) are adapted to their specific purpose

The first machine is a general-use analyser. It can measure (NO₃+NO₂), NO₂, NH₄, total dissolved N, PO₄, SO₄, and Cl. For most ions, the measurement range falls within 10 to 2000 µmol/l, whereas the measurement range is lower for PO₄ (0.2 to 16 µmol/l) and NO₂ (2 to 70 µmol/l). The substrate is usually fresh water, but with some adaptations BaCl₂- and K₂SO₄ extracts, and saline samples can be analysed.

Our second and newer segmented flow analyzer is dedicated to low concentrations of (NO₃+NO₂), NO₂, NH₄ and PO₄. The measurement range of PO₄ and NO₂ is 0,1 to 1,0 µmol/l, for (NO₃+NO₂) it is 1 to 20 µmol/l and NH₄ is quantified between 0.5 to 7 µmol/l. This analyzer is fitted with detector-correction lines which allows the analysis of marine water samples. Out of range-samples can be diluted automatically.

Inductively Coupled Plasma - optical emission spectrometry (ICP-OES) and Atomic Absorption Spectroscopy (AAS)

Atomic absorption (or emission) spectroscopy is a relatively cheap and simple technique that uses the absorption (or emission) of light by free atoms in the gaseous state for a quantitative determination of chemical elements. For a greater sensitivity across a wider range of elements the BioGeoChemistry lab uses inductively coupled plasma – optical emission spectroscopy (ICP-OES) where the sample is introduced in a plasma to produce excited atoms and ions that emit light at specific wavelengths characteristic for a particular element as they transition to a lower energy level.

The samples we measure are either water based liquids or in acid digested solids. Acid digestion of samples is typically performed using HNO₃/ HCl or HF/ H₂SO₄. A microwave oven is available to improve digestion by increased temperature and pressure.

Elemental (EA) and total organic carbon (TOC) analyzers

The elemental analyzer (EA) is a high temperature combustion unit used for the simultaneous quantitative analysis of the bulk carbon, nitrogen, sulphur and hydrogen in solid samples. The instrument can be modified to measure total inorganic carbon in a solid using a soliTIC module.

To measure carbon and total nitrogen in filtered water and aqueous extracts our lab is equipped with two total organic carbon (TOC) analysers. One of the systems is more robust and is generally used for ‘dirty’ samples or aqueous extracts whilst the other is used for freshwater and to measure low carbon concentrations in seawater

Stable isotope facilities

The stable isotope facility of IBED supports the research within the Institute, at UvA as well as other academic institutions and organizations in the areas of biogeochemistry, ecology, paleoecology, forensics, microbiology and nutrition.

The measurement of stable isotopes is a useful tool in many fields of study such as ecological, forensic and biological research. The natural differences in the stable isotopic composition can be used for example to determine the geographical origin of samples like agricultural products. Labelled chemicals can be used in the investigation of pathway or food web studies. The advantages of using labelled chemicals are that they are as harmless as their natural form, and they behave the same in the environment.

Isotope Ratio Mass Spectrometry (IRMS) detector

Our laboratory is equipped with 2 isotope ratio mass spectrometers (IRMS). An IRMS detector is a high precision mass spectrometer which can measure the in the natural abundant isotope ratio. Our systems are suitable of the measurement of light stable isotopes of carbon (¹²C/¹³C), nitrogen (¹⁴N/¹⁵N), hydrogen (¹H/²H), oxygen (¹⁶O/¹⁸O) and sulphur (³²S/³⁴S). Both IRMS detectors can be coupled with different inlet instruments making it possible to analyze a broad range of sample types (solid, liquid, gas and compound specific analyses).

Both IRMS detectors in our lab are continuous flow isotope ratio mass spectrometers. An IRMS differs from conventional mass spectrometers because it uses a strong electromagnetic field to separate the isotopic different masses (sector instrument) and is simultaneously detecting the ions with multiple collector analysis. This technique enables high accuracy and precision in the measurement of stable isotopes compared to other mass spectrometers.

Inlet instruments

An inlet instrument in necessary for stable isotope analysis because an Isotope Ratio Mass Spectrometry (IRMS) detector can only measure samples that are in gaseous state. Most of our inlet instruments can be used both as a standalone instrument for quantitative analyses and can be coupled with IRMS for a combined quantitative and isotopic ratio analysis. The inlet instruments have been optimized for accurate and precise isotopic measurement.

EA (Element Analyzer)

The elemental analyzer is a high temperature combustion unit used for the simultaneous quantitative analysis of the bulk carbon, nitrogen, sulphur, hydrogen and oxygen in solid samples. The combusted gasses are focused and transferred to the Isotope Ratio Mass Spectrometer (IRMS) for isotope ratio measurement

Total Organic Carbon Analyzer (TOC)

The Total Organic Carbon Analyzer (TOC) is a high temperature combustion system for the analysis of organic and inorganic carbon and total nitrogen in (soil) extracts or liquid samples like freshwater or seawater. Before Isotope Ratio Mass Spectrometry (IRMS) analysis, the combusted gasses pass through a focusing unit and are transferred to the IRMS for isotope ratio analysis. High precision (SD < 0.15‰) and accuracy (R2= 0.9997) is achieved with this TOC-IRMS system in ¹³C-DOC measurements. For this, various samples in a wide range of concentrations (0.2-150 mg C/L) and with different injection volumes (0.05-3ml) were analyzed.

GC-FID/Mass Spectrometry

Our GC-(quadrupole) Mass Spectrometry system with PTV and split/splitless injectors, can be used as stand-alone GC-MS system with FID and MS detection or coupled to the Isotope Ratio Mass Spectrometer (IRMS) using a GC5 interface for compound specific isotope ratio analysis of carbon, nitrogen, hydrogen or oxygen.

Trace gas

Our gas pre-concentrator can concentrate gasses such as CO₂, CH₄ and N₂O from gas samples using cryogenic traps. The concentrated gas is then transferred to the Isotope Ratio Mass Spectrometer (IRMS) for the isotope ratio measurement of carbon or nitrogen. This technique can be a useful asset in e.g. incubation studies.

Inorganic Analyses

The analysis of the inorganic components is roughly divided in two parts: most cations are routinely measured with inductively coupled plasma coupled to an optical emission spectrometer (ICP-OES), whereas mainly anionic nutrients are quantified with a segmented flow analyser (AA).
With these analysers the nutrients are routinely measured in aqueous samples, such as surface water and seawater, and in soil extracts. The two AA machines available (produced by Skalar, Breda, the Netherlands) are adapted to their specific purpose.

Skalar

The first machine is a general-use analyser. It can measure (NO₃+NO₂), NO₂, NH₄, total dissolved N, PO₄, SO₄, and Cl. For most anions, the measurement range falls within 10 to 2000 µmol/l, whereas the measurement range is lower for PO₄ (0.2 to 16 µmol/l) and NO₂ (2 to 70 µmol/l). The substrate is usually fresh water, but with some adaptations BaCl₂- and K₂SO₄ extracts, and saline samples can be analysed.

Our second and newer auto-analyser is dedicated to low concentrations of (NO₃+NO₂), NO₂, NH₄ and PO₄. The measurement range of PO₄ and NO₂ is 0,1 to 1,0 µmol/l, for (NO₃+NO₂) it is 1 to 20 µmol/l and NH₄ is quantified between 0.5 to 7 µmol/l. This analyser is fitted with detector-correction lines which allows the analysis of marine water samples. Out of range-samples can be diluted automatically.

Inductively Coupled Plasma (ICP) and Atomic Absorption Spectroscopy (AAS)

For the analysis of trace elements and heavy metals in acid digested soils or liquid samples.

Acid digestion of samples are typically performed with HNO₃/ HCl with a microwave (Paar Physica Multiwave) or with HF/H₂SO₄ of soil or organic material.

Contact information

Please contact: IBED-lab-science@uva.nl