Soil Methods
pH Value of Soils
SOP: 2010
UKAS accredited; MCERTS accredited
Measurement of the pH of a 2:1 water extract of a dried and ground soil sample using a pH meter.
Electrical Conductivity of Soils
SOP: 2020
Measurement of the electrical conductivity of a 2:1 water extract using a conductivity meter.
Moisture and Stone Content of Soils
SOP: 2030
MCERTS requirement
Determination of moisture and stone content of soil as percentages of its dry mass obtained after drying at <37°C.
Soil Description
SOP: 2040
MCERTS requirement
An as received soil is described in accordance with BS5930:2015 Code of practice for ground investigation.
Water Soluble Boron in Soils
SOP: 2120
UKAS accredited; MCERTS accredited
Analysis of a water extract of boron prepared from an aliquot of a dried and ground soil sample by inductively coupled plasma-optical emission spectroscopy (ICP-OES).
Water Soluble Sulphate in Soils
SOP: 2120
UKAS accredited; MCERTS accredited
Analysis of a water extract of sulphate prepared from an aliquot of a dried and ground soil sample by inductively coupled plasma-optical emission spectroscopy (ICP-OES).
Total Sulphur in Soils
SOP: 2175
UKAS accredited; MCERTS accredited
Total sulphur in a soil sample is determined by high temperature combustion in oxygen using an elemental analyser. The resultant sulphur dioxide is measured by infrared (IR) detection.
Sulphur (Elemental) in Soils by HPLC
SOP: 2180
UKAS accredited; MCERTS accredited
Aliquots of dried and ground soil are extracted into dichloromethane. The filtered extracts are analysed by high performance liquid chromatography (HPLC) using ultraviolet detection at 263nm.
Water Soluble Chloride in Soils
SOP: 2220
UKAS accredited; MCERTS accredited
Analysis of a water extract of chloride prepared from an aliquot of a dried and ground soil sample by discrete analyser using ferric nitrate / mercuric thiocyanate.
Cyanides & Thiocyanate in Soils
SOP: 2300
UKAS accredited; MCERTS accredited
Aliquots of dried and ground soil are extracted into 1M sodium hydroxide.
Free cyanide: Automated acid distillation followed by colorimetric development with chloramine-T and pyridine/barbituric acid. Intensity of colour at 610nm is measured.
Total cyanide by UV decomposition of complex bound cyanides with measurement of resulting free cyanide as above.
Complex cyanide determined by difference.
Thiocyanate is converted to cyanogen chloride which reacts with chloramine-T and 1.3-dimethylbarbituric acid/isonicotinic acid. Intensity of colour measured at 600nm.
Sulphide in Soils
SOP: 2322
UKAS accredited; MCERTS accredited
Sulphide is released from dried and ground samples as hydrogen sulphide by steam distillation with sulphuric acid. The hydrogen sulphide is collected in a solution of 0.5M sodium hydroxide. Sulphide is then analysed by automated colorimetric analysis on an Aquakem 600 discrete analyser using N,N–dimethyl-p-phenylenediamine.
Total Nitrogen in Soils
SOP: 2340
High temperature combustion of the sample in oxygen using an elemental analyser. The resultant nitrogen gas is measured by thermal conductivity detection.
Extractable Cations in Soils
SOP: 2400
Cations: potassium, magnesium, calcium, sodium
Soil extracts are prepared by extracting dried and ground soil samples with ammonium nitrate solution. Cations are determined by inductively coupled plasma – mass spectrometry (ICP-MS).
Extractable Phosphate in Soils
SOP: 2420
Soil extracts are prepared by extracting dried and ground soil samples with sodium hydrogen carbonate solution. Phosphate is determined by ‘Aquakem 600’ discrete analyser using ammonium molybdate.
Extractable Ammonium in Soils
SOP: 2425
UKAS accredited; MCERTS accredited
Soil extracts are prepared by extracting dried and ground soil samples with potassium chloride solution. Ammonium is determined by ‘Aquakem 600’ discrete analyser using sodium salicylate and sodium dichloroisocyanurate.
Total Sulphate in Soils
SOP: 2430
UKAS accredited; MCERTS accredited
Acid digestion of a sample aliquot in a heating block followed by the determination of sulphate in the extract by inductively coupled plasma – optical emission spectroscopy (ICP-OES).
Note that the digest may be by either aqua-regia or hydrochloric acid, dependant upon client requirements. Both are MCERTS accredited.
Acid Soluble Metals in Soils
SOP: 2450
UKAS accredited; MCERTS accredited
UKAS & MCERTS accredited: arsenic; barium; cadmium; chromium; cobalt; copper; lead; manganese; mercury; molybdenum; nickel; selenium; zinc
UKAS accredited: beryllium; vanadium
Acid digestion of a sample aliquot in a heating block followed by determination of metals in the extract by inductively coupled plasma – mass spectrometry (ICP-MS).
Hexavalent Chromium in Soils
SOP: 2490
Soil extracts are prepared by extracting dried and ground soil samples into boiling water. Chromium [VI] is determined by ‘Aquakem 600’ discrete analyser using 1,5-diphenylcarbazide.
Loss on Ignition
SOP: 2610
UKAS accredited; MCERTS accredited
Determination of the proportion by mass that is lost from a soil by ignition at 440°C or 550°C.
Total Organic Carbon in Soils
SOP: 2625
UKAS accredited; MCERTS accredited
Total organic carbon (TOC)
The sample is first acidified to remove any inorganic carbon. Total organic carbon is then determined by high temperature combustion in oxygen using an elemental analyser. The resultant carbon dioxide is measured by infrared (IR) detection.
Total Petroleum Hydrocarbons (TPH) in Soils by GC-FID
SOP: 2670
UKAS accredited; MCERTS accredited
UKAS & MCERTS accredited: Total petroleum hydrocarbons in the range C6–C40
UKAS accredited: Gasoline Range Organics (GRO), Diesel Range Organics (DRO)
Optional carbon banding is available.
Extraction of an as received soil sample, following chemical drying with sodium sulphate, into dichloromethane followed by determination of total petroleum hydrocarbons by gas chromatography using flame ionisation detection (GC-FID).
Aliphatic/Aromatic Petroleum Hydrocarbons in Soils by GCxGC-FID
SOP: 2680
UKAS accredited; MCERTS accredited
UKAS accredited: all bands in the range C8–C40
MCERTS accredited: all bands in the range C8–C35
aliphatic banding: >C5–C6, >C6–C8,>C8–C10, >C10–C12, >C12–C16, >C16–C21, >C21– C35, >C35– C44
aromatics banding: >C5–C7, >C7–C8, >C8–C10, >C10–C12, >C12–C16, >C16– C21, >C21– C35, >C35– C44
Extraction of an as received soil sample, following chemical drying with sodium sulphate, into dichloromethane followed by determination of total petroleum hydrocarbons by two dimensional gas chromatography using flame ionisation detection (GCxGC-FID).
Speciated Polynuclear Aromatic Hydrocarbons (PAHs) in Soils by GC-FID
SOP: 2700
UKAS accredited; MCERTS accredited
Acenaphthene; acenaphthylene; anthracene; benzo[a]anthracene; benzo[a]pyrene; benzo[b]fluoranthene; benzo[ghi]perylene; benzo[k]fluoranthene; chrysene; dibenz[ah]anthracene; fluoranthene; fluorene; indeno[123cd]pyrene; naphthalene; phenanthrene; pyrene
Extraction of a dried and ground soil sample into dichloromethane followed by the determination of polynuclear aromatic hydrocarbons by gas chromatography using flame ionisation detection (GC-FID).
Volatile Organic Compounds (VOCs) in Soils by Headspace GC-MS
SOP: 2760
UKAS accredited; MCERTS accredited
UKAS & MCERTS accredited: please refer to UKAS schedule for individually accredited compounds.
Analysis of an as received soil sample for volatile organic compounds by automated headspace gas chromatography with mass spectrometric detection (HS-GC-MS).
Based upon USEPA Method 8260
Semi-Volatile Organic Compounds (SVOCs) in Soils by GC-MS
SOP: 2790
UKAS accredited; MCERTS accredited
UKAS & MCERTS accredited. Base upon USEPA Method 8270
Extraction of an as received soil sample into dichloromethane followed by the determination of semi-volatile organic compounds by gas chromatography using mass spectrometric detection (GC-MS).
Speciated Polynuclear Aromatic Hydrocarbons (PAHs) in Soils by GC-MS
SOP: 2800
UKAS accredited; MCERTS accredited
UKAS & MCERTS accredited: acenaphthene; anthracene; benzo[a]anthracene; benzo[a]pyrene; benzo[b]fluoranthene; benzo[ghi]perylene; chrysene; fluoranthene; fluorene; indeno[123cd]pyrene; naphthalene; phenanthrene; pyrene
UKAS accredited: acenaphthylene; benzo[k]fluoranthene; dibenz[ah]anthracene
Extraction of a dried and ground soil sample into dichloromethane followed by the determination of polynuclear aromatic hydrocarbons by gas chromatography with mass spectrometric detection (GC-MS).
