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ANALYTICAL CHEMISTRY UNIT - FACILITIES
Following a £730,000 refurbishment in 2021, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), the Analytical Chemistry Unit offers state-of-the-art facilities, with flagship laboratories providing chemical services in support of strategic agricultural science.
Our facilities include: a range of preparation labs designed for: sample registration, weighing, storage of imported soils and clean labs with facilities for shaking, dilution, extraction and digestion. A suite of air-conditioned ultra-clean specialist laboratories equipped with the most advanced instrumentation available, provide high level performance in terms of speed, accuracy, precision, and reliability.
Extraction and digestion
Our extraction and digestion preparation facilities are strictly controlled to eliminate contamination issues, and quality is monitored using certified and in-house standard materials.
The digestion laboratory uses automated heating blocks and hot plates for aqua regia and nitric/perchloric digestion, used for the determination of major and trace elements in both soil and plant material. Microwave digestion is used for closed tube procedures including the determination of boron.
The extraction laboratory processes soil samples using several standard procedures; these include pH, ammonium nitrate exchangeable cation extracts, sodium bicarbonate (Olsen P) and Mehlich III extractions.
Major and trace element analysis
Major and trace element analysis of soil, plant material and waters is carried out using Inductively Coupled Plasma (ICP) Spectrometry.
Optical Emission Spectrometry (ICP-OES) is used for samples with element concentrations ranging from percentages to parts per million (ppm). Mass Spectrometry (ICP-MS) is used when ultra-low-level analysis is required (parts per billion - ppb).
ICP-MS linked to a high-pressure liquid chromatography system (LC-ICP-MS) is also used as a research tool for arsenic and selenium speciation.
- Perkin Elmer Optima 7300DV ICP-OES
- Agilent 5900 SVDV ICP-OES
- Perkin Elmer NexION 300X ICP-MS with optional link to Perkin Elmer Flexar HPLC System
Combustion analysis - total nitrogen and carbon
Total nitrogen and total carbon in soil and plant material is determined using one of two combustion analysers, both based on a modified version of the Dumas method. Carbon is detected by Non-Dispersive Infrared (NDIR) and nitrogen using a Thermal Conductivity (TC) cell. The two instruments have the capability of processing several thousand samples each year and use ceramic boats and foil cups to cover a variety of sample materials and weights.
- Total N and C Combustion Analyser Leco TruMac
- Total N and C Combustion Analyser Leco CN628
Anion (colourimetric) analysis
Colourimetric Continuous Flow Analysis (CFA) is routinely used for the determination of nitrate-N, nitrite-N, ammonia-N, chloride and phosphate-P, in soil and plant extracts/digests and environmental samples. Total N is also determined using an online UV persulphate oxidation stage.
- Skalar San++Colourimetric Continuous flow Analyser
Carbon analysis
Total organic carbon (TOC) in solution, measured as Non Purgeable Organic Carbon (NPOC) is determined on a UV persulphate oxidation instrument. Samples include high salt extracts of soil (K2SO4), rain, drainage water and soil solutions.
Inorganic carbon is determined in soil by treating with phosphoric acid and then heated in the closed system of the Primacs AIC Analyser. Inorganic carbon in the soil is liberated as carbon dioxide gas and measured by Non-Dispersive Infrared (NDIR) detection.
- Shimadzu TOC-V WP Total Organic Carbon Analyser (UV Oxidation)
- Skalar Primacs AIC Analyser (IC)