Flame Emission Spectrophotometers - These instruments are used to measure cations in aqueous solution, such as calcium, magnesium, sodium and potassium down to parts per million. Spectrophotometry measures the absorption and emission of photons as electrons of a specific element are excited to higher orbitals and drop back to the ground state.
UV-visible spectrophotometry - This technique is mostly used to determine nitrogen and phosphate concentrations in the parts per million range. In this case, the absorption of light at a specific wavelength as it passes through an aqueous solution is measured.
pH, Ion Sensitive Electrodes and Electrical Conductivity - pH is the negative logarithm of the hydrogen ion concentration of a solution. A probe is introduced into the solution to be measured, which gives a read-out on a meter. Ion Sensitive Electrodes work in a similar way and are used to measure the concentration of ions such as nitrate and chloride. Electrical Conductivity is a measure of the total ionic solutes. It provides a useful measure of ionic strength, but does not identify which ions are present.
Balances - The laboratories have several extremely accurate balances, which read down to ten thousandths of a gram. These balances are connected to a personal computers, and can download data directly onto spreadsheets. This brings the advantages of speed, accuracy, precision, and the ability to handle a large volumes of data.
Malvern Laser Particle Sizer - The Malvern Mastersizer 2000 is a laser particle sizer used to measure the particle size distribution of soils and sediments. It allows for the measurement of particles ranging from 0.02µm to 2mm. The Mastersizer is connected to a personal computer, on which the particle size data can be displayed in both table and graph form. The data can also be exported to a spreadsheet for more sophisticated analyses.
Armfield Engineering Tilting Flume - Hydraulics - The Soils and Sediments Laboratory houses a tilting flume which is used to simulate the flow dynamics of rivers. The gradient, discharge, depth and bed type can all be varied with relative ease. The flume also has a wave generator, which can produce pulses of varying frequency and amplitude to mimic lacustrine and shallow marine conditions.
Sieving, Pulverising and Milling - The Soils And Sediments Laboratory also contains a variety of sieves ranging from large diameter gravel sieves with metal meshes up to 36mm to small nylon sieves with apertures of only 5µm. Although the sieves can be used for particle size analysis, they are usually employed for separating plant and animal fossils, pebbles, or other material for subsequent analysis. The laboratories have several sieve shakers which can be used for either wet or dry sieving of soils and sediments. The pulveriser and ball mill are used to comminute soils and sediments prior to various physical and chemical analyses.
Bartington Magnetic Susceptibility Meters - Magnetic Susceptibility - is used to measure the magnetic susceptibility of a variety of soils and sediments. Magentic susceptibility depends on the amount, type and particle size of the ferro-magnetic minerals present. The meter may be used with a scanning loop to measure cores of sediment, or with a well-type sensor for discrete samples.
ICP-OES - Inductively Coupled Plasma - Optical Emission Spectral analyses offers a fast multi-element technique with a dynamic linear range and moderate-low detection limits (~0.2-100 parts per billion). A new Perkin-Elmer ICP-OES became available in the Geography Science Laboratories in summer 2006.