Melbourne School of Land and Environment Department of Forest and Ecosystem Science

pH

Instruments: Radiometer PHM240, TPS Labchem, Hanna field probes, pH test strips by Macherey-nagal.

Principle of Operation:The pH value of a samples relates to its acidity. The test is carried out on a liquid eg water samples or a suspension of a soil (1:5 in water and 1:5 in CaCl₂). In soil samples pH effects the solubility and activity of various biologically important elements and processes.

Current Analysis: pH in water, soil extracts (1:5 water and 1:5 CaCl₂) and other liquids

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pH EC Radiometer

EC - Electrical Conductivity

Instruments: Radiometer CDM230, TPS Labchem, Osmometers.

Principle of Operation: Electrical conductivity is a measure of the concentration of soluble salts in solution. Soluble salts include Na⁺, Mg²⁺, Ca²⁺ with Cl^-, SO₄^2- and HCO₃^-.

Current Analysis: EC in liquid samples (soil extracts are 1:5 soil:water)

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pH EC Radiometer

UV-Vis - Ultra Violet - Visible Spectrophotometer

Instruments: Cary 300, Cary 50 with fiber optic probe

Principle of Operation: The UV-Vis Spectrophotometer is used to measure the color intensity of a sample in the range 200nm - 800nm. A color complexing agent is usually added to produce a color of known wavelength. The Carey 300 UV-Vis instrument has scanning capabilities.

Current Analysis: Walkley and Black Total C in soil, microbial biomass, PO₄-P

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Ultra Violet - Visible Spectrophotometer

EA - Elemental Analysis (Dumas Combustion)

Instrument: LECO CHN2000

Principle of Operation: The LECO CHN2000 is an elemental combustion system that burns your sample at 950^oC in a stream of oxygen to convert elemental carbon, nitrogen and hydrogen to CO₂, N₂ and NO₂, H₂0 and other gases, which are then reduced to C0₂, N₂, H₂ gas. The C and H are analysed by successive infra red cells and the N₂ is detected by a thermal conductivity cell.

Current Analysis: Soil and plant total C, total N, total H

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Elemental Analysis LECO

IRMS - Isotope Ratio Mass Spectrometer

Instrument: GV Instruments Micromass IsoPrime with Eurovector EA and Trace Gas module.

Principle of Operation: The Isotope Ratio Mass Spectrometry uses mass - charge ratio in the gas phase to measure relative isotopic abundance of C12/13 and N14/15 (capability to analyze H,O,S). Analytes are ionised by a source, passed through a magnetic field within a vacuum flight tube and detected by farady cup (ion charge). Solid and liquid samples are combusted, oxidized and reduced appropriately, separated on a GC column and fed into the mass spectrometer via an open slit. The IRMS is also equipped with a trace gas analysis module.

Current Analysis: ¹³C/¹²C and ¹⁵N/¹⁴N in gas, plant and soil samples (capability to do liquid samples, hydrogen, oxygen and sulphur)

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IRMS

ICP-AES - Inductively Coupled Plasma

Instrument: Varian Vista Pro Axial.

Principle of Operation: The ICP aspirates a fine mist of liquid sample (water, diluted sap, soil / plant digest or extract) into an Argon Plasma (up to 10,000K). Elements of interest are excited and emit characteristic wavelengths corresponding to their discrete transition energy levels. The emitted energy (spectral line) is detected on a CCD chip.

Current Analysis: Plant nutrients (Ca, Mg, Mn, K, P, S, Cu, B, Sr, Mn), soil exchangeable cations (Ca, Mg, Na, K, Fe), water cations (Ca, Mg, Na, K, Sr), soil boron, soil sulphur, soil total phosphorus.

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ICP - AES

SFA - Segmented Flow Analysis

Instrument: Bran and Luebbe AA3 Segmented Flow Analyser with dual channel.

Principle of Operation: Segmented Flow Analysis relies on a colorimetric reaction that is developed in an online series of tubes, mixing coils and a heating bath. The flow is segmented by air bubbles which minimize band broadening.

Current Analysis: Soil, plant or water, NO₃-N NO₂-N, NH₄-N (scope to complete PO₄-P, Cl, Al)

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Segmented Flow Analyser

CE - Capillary Electrophoresis

Instrument: Beckman Coulter P/ACE CEQ.

Principle of Operation: Capillary Electrophoresis (CE) uses high current passed through a buffer gel within a silica capillary of 0.05mm diameter, separation of analytes is based on the charge and size and detected by PDA (photometric diode array).

Current Analysis: proteins, anions, cations and organic acids in phloem sap and plant leaves

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Capillary Electophoresis

HPLC - High Performance Liquid Chromatography

Instruments: Dionex DX-2500, Dionex DX-80, Waters 620, Varian

Principle of Operation: The HPLC pumps an eluent (mobile phase) under high pressure through appropriate stationary phases (column). Sample (liquid) component separation relies on the interaction of the analyte and eluent with a stationary phase causing separation in time and space. Detection can vary depending on the analysis; the DX-2500 has a chemical detecter for EC and Pulsed Ampiometry Detection (PAD), the Waters and Varian instruments have Uv-Vis and Fluorescence Detectors.

Current Analysis: anions, organic acids, starch, sugars in various matrices: water, plant, sap. The Waters instrument is running ergosterol and other reverse phased methods. The Varian instrument is operated by the CRC-Wood Innovations.

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High Performance Liquid Chromatography DX2500

HPMSC - High Precision Multi Scanning Calorimetry

Instrument: Calorimetry Science Corporation (CSC) MC-DSC. (Three identical units)

Principle of Operation: The MC-DSC can measure very small changes in energy. Sample cells are thermally controlled and can differentiate sample contribution to the heat load.

Current Analysis: Plant respiration profiles used for analysis of plant stress (water, nutrient, salt etc).

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Calorimeter High Precision

Respicond

Instrument: Respicond custom 250L, 96 well simultaneous analysis

Principle of Operation: The Respicond is a 96 chamber instrument that can "simultaneously" measure the respiration rate of samples (usually soil). The chamber is thermostatically insulated in a large water bath. The CO₂ evolved by the sample is absorbed onto a solution of potassium hydroxide of known concentration. This changes the conductivity of that solution which is measured across platinum electrodes and recorded automatically by a computer at defined time intervals.

Current Analysis: Soil and wood respiration profiles

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Respicond

GC - Gas Chromatograph

Instruments: Shimadzu 17A GC, Shimadzu 17A modified for gas work.

Principle of Operation: Gas chromatography uses the flow of gases (mobile phase) over a stationary phase (the column) and an analytes interaction between the two phases to separate molecules of interest. GC-Liquid has an FID detector and the GC-Gas has an ECD (CO₂and N₂0) and FID (CH₄).

Current Analysis: Liquid GC - sugars - cyclitols including inositol, myo-inositol. The Gas GC is set up to analyse methane, nitrous oxide and carbon dioxide.

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GC for Gas Samples

GC for Liquid Samples