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Metals Testing in Water and Soil

Alfa Chemistry's laboratories can analyze water, leachate, waste, sediment, and soil to test metals that are harmful to the environment and human health. Our experts use inductively coupled plasma (ICP) combined with optical emission spectroscopy (OES) or mass spectrometry (MS) to test various metals. Common metals tested include, but are not limited to, arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, zinc, beryllium, boron, aluminum, iron, silver, tin, uranium, calcium, sodium, potassium, and magnesium.

We also provide semi-quantitative scanning. Reporting limits for target metals are usually in ppb (parts per billion) but can be as low as ppt (parts per trillion).

Sample Preparation

Prepare water samples for metal testing

The water samples are acidified and filtered in the laboratory or on-site. The water should be stored in nitric acid so that the pH value is lower than 2. This converts or maintains the metal as a soluble salt so that the metal does not convert to an insoluble salt, falls out of the solution and gives incorrect low values.

If a dissolved metal test is required, the sample should be filtered into nitric acid through a 0.45 µm filter on site. Once stored, the maximum recommended storage time is six months.

If you need to perform a total metal test in water, you can add nitric acid directly to the sample water. The metal will be leached from the solids present in the water and can only be operated by qualified personnel.

Prepare water samples for metal testing

Prepare soil samples for metal testing

Depending on the required method, various acids (such as HF, HNO3 or aqua regia) can be used to extract soil samples and then digest them in a heat block or microwave in a closed system. Other extraction methods can be used to extract the available metals, such as EDTA or water. Once the metals are extracted, the digested sample is filtered and ready for analysis by ICP.

The maximum recommended storage time for soil samples is six months. If you follow best practices, take samples in airtight containers, keep them cool, and avoid direct sunlight.

Testing Methods

Testing metals using inductively coupled plasma (ICP)

ICP is a technology that can determine the concentration of trace major elements, and can detect most elements in the periodic table.

The solution containing the dissolved metal is sucked through the atomizer into the atomization chamber of the ICP instrument, where it is mixed with argon to form a fine aerosol. This aerosol then enters the plasma.

Analyze a series of solutions with known concentrations to obtain a calibration curve for each element. The instrument software compares the sample with the calibration curve and calculates the concentration of each element.

Testing metals using inductively coupled plasma (ICP)

Testing Standards

  • ASTM E1613 - 12 Standard Test Method for Determination of Lead by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES), Flame Atomic Absorption Spectrometry (FAAS), or Graphite Furnace Atomic Absorption Spectrometry (GFAAS) Techniques (Withdrawn 2021)

Contact Alfa Chemistry to learn more about our soil and water analysis, including metal and heavy metal testing.

Our products and services are for research use only and cannot be used for any clinical purpose.