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Calibration Solutions and Kits for radiello® Diffusive Air Sampler

By: Klaus Buckendahl, Analytix Volume 6 Article 5

Standard solutions and kits for air sampling of a wide range of air-borne contaminants

By Klaus Buckendahl, European Sales Development Manger … kbuckend@europe.sial.com

In 2006, Supelco, a member of the Sigma-Aldrich family, in collaboration with the Institi Clinici Scientifici Maugeri (ICSM), Padova, Italy, partook in a joint venture in which Supelco became the exclusive world-wide distributor of radiello products and accessories.

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What is radiello?

radiello is a patented revolutionary diffusive sampler design. The radial symmetry design gives significantly faster sampling rates, typically 3- to 8-fold faster than common axial diffusive samplers. This speed permits passive sampling for short-term measurements, a feat not attainable before radiello.

  • Faster sampling due to high uptake rates
  • High analyte capacity and broader concentration ranges due to larger adsorbent bed
  • More reliable results due to experimentally determined sampling rates
  • Economical use because of the reusable hardware

Typical applications for radiello are indoor sampling, outdoor sampling, and industrial hygiene measurements (work place environments).

The radiello diffusive samplers have been designed for the following air-borne contaminants:

  • Aldehydes
  • VOCs and BTEX (with both solvent and thermal desorption)
  • Nitrogen and Sulfur Dioxide (NO2 and SO2)
  • Hydrogen fluoride (HF)
  • Hydrogen chloride (HCl)
  • Ozone (O3)
  • Phenols (with thermal desorption)
  • Hydrogen sulfide (H2S)
  • Ammonia (NH3)
  • Anesthetic Gases and Vapors

To analyze the loaded radiello cartridges after sampling, we now offer calibration kits and solutions. Calibration solutions are available for H2S and aldehyde analysis, and calibration kits with pre-spiked cartridges for BTEX and VOC determination. Details appear below.

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Calibration solutions for radiello cartridges

H2S (Hydrogen Sulfide) calibration standard

This standard consists of a methylene blue concentrate that, once diluted 1:50, provides the same absorbance value of hydrogen sulfide at 665 nm at a concentration of 1.145 μg/L sulfide ion. This concentration is the highest absorbance value within the linear range of the spectrophotometer and can be used as a stock solution to prepare standards for the calibration curve. One pack is suitable for preparing 50 calibration curves using the recipe described in the accompanying table. The standard is stable for at least one year.

Table 1.Preparation of H2S calibration curve using RAD171

Aldehyde calibration standard

This standard consists of nine different 2,4- dinitrophenylhydrazone derivatives (2,4-DNPH) diluted in 10 mL of acetonitrile. The concentrations for each compound appear in the accompanying table. Actual concentrations are certified for each lot and provided on the data sheet. The solution is shipped in a crimp cap vial with a pierceable septum, and is stable for at least 4 months when stored at 4°C in the dark.

Table 2.Composition of the aldehyde calibration standard for radiello

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Calibration kits

The radiello calibration kits can be used to establish a calibration curve, to perform quality control runs and to do system proficiency testing, which gives analysts the opportunity to determine the efficiency of their desorption procedures.

The type of cartridge in each kit is application-dependent. All kits consist of twelve cartridges: Three cartridges are blanks and nine are preloaded with analytes in three different concentration groups. The spiked concen trations are shown in the tables accompanying each kit description. The values shown are indicative; actual concentrations are certified for each lot. The cartridges are stable for at least four months when stored at 4°C.

BTEX calibration kit (CS2 desorption)

This calibration kit is designed for the analysis of BTEX in urban environments followed by chemical desorption with CS2. The kit may be used for both routine calibration and quality control. The kit consists of twelve Code 130 Cartridge Adsorbents (Cat. No. RAD130). The preloaded BTEX compounds simulate 7 days exposure (100,080 minutes). The values shown in the following table are representative of the pre-loaded analyte levels.

Table 3.Simulated analyte concentrations (μg/m3) of BTEX/ CS2 Kit (equivalent to 7 days exposure)

BTEX calibration kit (thermal desorption)

This kit is designed for the analysis of BTEX in urban environments followed by thermal desorption. It can be used for both routine calibration and quality control. The kit consists of twelve Code 145 Cartridge Adsorbents (Cat. No. RAD145). The BTEX preloaded simulate 7 day exposures (100,080 minutes). BTEX is spiked on the cartridges by injecting vaporized BTEX standards in methanol under nitrogen flow. A methanol peak may be visible during chromatographic analysis.

Table 4.Simulated analyte concentrations (μg/m3) of BTEX/TD Kit (equivalent to 7 days exposure)

VOC calibration kit (workplace environment)

This kit is ideal for conducting scheduled quality control runs when analyzing VOCs in workplace environments. It comprises twelve Code 130 Cartridge Adsorbents (Cat. No. RAD130). VOCs are spiked on the cartridges by injecting vaporized VOC standards in CS2 under nitrogen flow. The spiked VOCs represent a broad range of polarity, and the spiked concentrations represent 0.5-, 1- and 2-times the threshold limit values (TLV) for each compound. The VOC cartridges simulate 8 hours exposure (480 minutes).

Table 5.Simulated analyte concentrations (μg/m3) of VOC Kit (equivalent to 8 hours exposure)

For additional calibration standards and solutions, please refer to the Sigma-Aldrich Analytical Standards Catalog, or visit www.sigma-aldrich.com/standards.

For more details and information on the radiello diffusive sampler please request the radiello brochure (IXV) or visit our radiello web site www.sigma-aldrich.com/radiello.

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