Downloadable Chain of custody
he Chain of custody is a document of fundamental importance to correctly manage samples information during sampling, transport, analysis and reporting. It guarantees the traceability of every sample. Mérieux NutriSciences offers templates that can be downloaded from the website and then filled in to accompany samples.
In the remediation of contaminated sites, the study and monitoring of the spread of soil contaminants (present in interstitial soil gases) are a good way in all the stages of the environmental process and they are used for:
- site’s conceptual model formulation during site characterization;
- analysis of the potential hygienic-health risk resulting from the inhalation of soil vapors (site-specific risk analysis);
- identification of test set and sampling site;
- assessment of specific remediation technologies.
The representative sampling of soil-gas is obtained by evaluating the variables relating to the chemical and physical properties of the substances to be analyzed, soil and subsoil characteristics, weather conditions and sampling techniques. The achievement of reliable data in the direct evaluation of indoor and outdoor air quality sometimes needs time and technical/financial resources which might exceed the size of the problem. If the risk of inhaling particulate can be considered negligible if compared to the risk of inhaling vapors, an alternative procedure based on the interstitial soil-gas measurements is defined. The leader of sampling and subsequent analysis of volatile organic compounds present in the air in indoor and outdoor concentrations of less than 5 ppm is the Canister method.
Why choosing Canister?
Canister is well-known for its easy use since it works with a reduced chain of components. It can be easily transported and it also allows the detection of a large number of volatile compounds, thus reaching a higher sensitivity compared to traditional methods (GC-FID1). Canister is a sampling system mainly composed of a vacuum metal casing and a valve -if required- to regulate its filling in a pre-set timeframe. The capacity of Mérieux NutriSciences Canisters amounts to 3.2 or 6 liters and valves (passive samplers) are ENTECH1 branded; both are lined with SILONITE®, a special material that makes Canister inert and reusable over time (after cleaning and vacuum setting). For their calibration, a digital flowmeter is used: together with Canister and the valve, it allows the calibration of the latter depending on sampling requirements. After being cleaned and prepared to be reused, the Canister lasts for about 15 days; after this period, it may have internal air micro-leakage that could compromise subsequent sampling and thus relevant analysis.
The advantages of Canister:
- No sample modification after sampling;
- No need to measure sample volume upon sampling;
- Wide range of choosing sampling intervals (from a few seconds to a week);
- Canister inner surface is inert compared to the pollutants present in the air sample;
- Detection of many compounds, including heat-sensitive ones;
- Sample is transferred from Canister to analysis tool running at low temperature;
- Multiple analyses and their repetition;
- High separation capacity and compound identification;
- Low possibility of Canister breaking (during transport and use);
- It is not necessary to know the concentration of pollutants in advance to identify Canister capacity;
- High or low concentrations of pollutants do not affect the sampling mode.
1 Gas chromatography (GC) and flame ionization detector (FID).
Mérieux NutriSciences laboratories belong to laboratories able to offer the Canister sampling service and relevant analysis and they differ from competitors thanks to the rental service. Moreover, besides making Mérieux NutriSciences professionalism available to customers and propose Canister as a highly effective and easy-to-use tool, the company can rent Canister on request and offer the relevant analyses of volatile organic compounds (VOCs). The control of volatile organic compounds with Canister method ensures a high degree of stability in compounds sampled in the periods after sampling and storage. The method of analysis used by Mérieux NutriSciences for the determination of VOCs is the EPA TO 15 1999 (determination of volatile organic compounds in ambient air sampled by Canister and analyzed by gas chromatograph with mass detector); such method is acknowledged by UNI CEI EN ISO/IEC 17025:2005 standard. The Canister also allows MADEP APH analysis (Massachusetts Department of Environmental Protection - Air Petroleum Hydrocarbons) in soil-gas: for this, Mérieux NutriSciences adopts MADEP APH method rev. 1 2009, not yet accredited: to date, it is the only method to evaluate hydrocarbons during their vapor phase in accordance with a risk-based corrective approach (i.e. with fractionated aliphatic and aromatic ranges).
The sampling of volatile organic/inorganic compounds is performed with flux chambers and it gives an estimate of the quantity of pollutant emitted from contaminated soil or contaminated fluids, depending on the unit of surface and unit of time. The sampling occurs through a cylindrical chamber open on one side and with a controlled environment. Inert and pure gases are introduced in a determined point and at a constant flow rate while the sampling of the required pollutant are performed through a second line; two further openings discharge the internal overpressure and control the internal microclimatic conditions of the support. The sampling of organic and inorganic compounds of different nature can be carried out.
Mérieux NutriSciences laboratories perform both the environmental monitoring at remediation plants to assess the presence of potentially radioactive dust, and the precautionary or final check to detect the presence of potentially radioactive dust. The company entrusts the evaluation of results to external qualified experts.