Whatman™ filters for soil testing

By extracting chemical compounds through pH and heat modulation, key elements such as nitrogen, phosphorus, pesticides and solids can be precisely measured. Whatman™ offers a range of products to support every stage of soil testing and ensure accurate, reliable results for better decision making in agricultural and environmental management.

Kjeldahl nitrogen analysis

Soil nitrogen content is typically measured using Kjeldahl techniques, which begin by collecting a precisely measured soil sample in a digestion tube. For this application, you can use Whatman™ low-nitrogen-content weighing boats and qualitative filter paper.

Soxhlet extraction

Before analysis by gas chromatography (GC), for example, soil samples may be prepared using Soxhlet extraction or microwave digestion. Extraction thimbles are widely used for this technique. To remove fine particles and protect your GC instruments, use specific syringe filters.

Spectrophotometry and chromatography

Most trace element tests are based on extracting soil and measuring the concentration of trace elements in the soil-free liquid phase using inductively coupled plasma atomic emission spectrometry (ICP-AES) or other techniques. Samples should be filtered through qualitative filter paper or a glass fiber filter to ensure that they will not clog nebulizers or interfere with injection into the analysis instrument. Samples digested with aqua regia may be filtered through an ashless filter paper.

Colorimetry for phosphorous analysis

Through soil phosphorus testing, the amount of phosphorus fertilizer required to achieve maximum plant growth can be determined. To determine the soil phosphorus content, the soil is extracted with a chemical solution, and the phosphorus content in the extract is measured by colorimetry. Filtration of the extract through a qualitative filter paper is generally required before analysis. If an automated method is used for determining phosphorus concentration, acid-resistant filter paper may be needed.

pH analysis

The pH of soil is a vital measurement that indicates how well the soil holds minerals. Some plants have very particular pH requirements. There are many different methods for measuring soil pH. Using litmus/pH paper is a quick and inexpensive way to measure soil pH when a pH meter is unavailable or when highly precise values are not necessary. When preparing your soil sample, weight the sample on weighing paper before adding water. Filter paper can be used to remove unnecessary particles from the suspension.

Whatman™ filters for sample clarification and solids retention

Some methods require that the liquid component of a solution be separated from the suspended solids before analysis. Cytiva offers a wide choice of cellulose filter papers with different flow rates, loading capacities and chemical resistances to support these applications.