Analysis of anions (F, Cl, Br, NO₂, NO₃, SO₄, PO₄, Ca, K, Li, Na, Mg) is possible with anion chromatography. This is equipped with a column oven, MSC and MSM module for sequential suppression, a peristaltic pump for suppressor regeneration and a built-in degasser. Detection and quantification of ions can be achieved using a conductivity and/or UV detector.

A Metrohm 858 autosampler with 127 positions on the carousel is available for sample introduction. The instrument also offers options for inline auto-filtration and auto-dilution of samples.

Sample requirements:

• ions can be quantified in aqueous samples including groundwater (borehole), surface water (dams, rivers, wetlands), municipal water, effluent and seawater. 

• When requesting analysis, please indicate the sample type and any treatments conducted or chemicals that were added during preparation of the sample. 

• Please indicate the presence of any toxic substances to ensure safe working conditions and appropriate disposal of samples. The unit reserves the right not to analyse samples containing hazardous waste or chemicals and may return these to the customer for disposal.

Sampling information:

• A minimum of 100ml sample is required for analysis of anions and cations. 

• Samples should be filtered using a 0.45µm nylon syringe filter to remove particles. Please do not use filter paper as this can introduce contaminants such as calcium or nitrate.

• Following collection and during transport keep samples in a cooler box on ice in the dark to minimise the growth and activity of micro-organisms in the sample.

• Select the correct clean container for sample storage/collection/preparation (Polypropylene and low-density polyethylene (LDPE) is the most suitable).

• Containers should be filled to the brim leaving no headspace prior to capping and sealing.

• Label samples with a permanent marker indicating sample identity or number and the date.

• If possible, record the conductivity of the sample or provide at least 200ml extra sample to enable measurement in the laboratory.

• Provide a list of samples, including sample description and identification number, with sample submission.

Guidelines for specific ions:

• Analysis and quantification of NO₃, NO₂ and PO₄ should be conducted within 48-hours following sampling.

• Samples used for analysis and quantification of NH₄ can be preserved by adding 100µl 1M (IC grade) nitric acid (HNO₃) for every 10ml sample immediately after collection or as soon as possible. Acidifying the sample is important to stabilise the ions in solution.

• If anion quantification will also be required, please collect a separate, non-acidified, sample and indicate on the container which sample is acidified.

• Br, Cl, F and SO₄ can be analysed up to 28 days after sampling.

O/H stable isotope analysis is possible withthe Los Gatos Research (LGR) GLA431-TLWIA, a liquid water triple isotope analyser. It is equipped with an autosampler and vaporiser module to introduce samples into the system.

The instrument makes use of off-axis integrated cavity output spectroscopy to simultaneously measure δ²H, δ¹⁷O, δ¹⁸O in liquid water samples.

Sample requirements:

• Collect at least 15 ml sample in air-tight containers to avoid evaporation.

• All samples should be free of debris and excess sediment, and preferably filtered using a 10-micron non-sterile nylon syringe filter.

• Clearly label samples using a permanent marker with sample details or number and date.

• Please indicate sample matrix (surface, ground, rain, sea water, xylem extracts).

• Store at ambient temperature until sent to the laboratory.

• If EC is above 2000 µS/cm, sample distillation would be required. Please indicate EC of sample during sample submission.