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![]() | ISO-CHEK® is the only filter-based sampling system that simultaneously traps and separates both monomers and oligomers at the point of collection for highly sensitive physical and chemical characterizations of diisocyanates including HDI, MDI, IPDI, HMDI, 2,4-TDI, and 2,6-TDI. The IRSST-developed ISO-CHEK offers rapid 15-minute sampling, stable samples, and a 40% reduction in sample preparation and analysis time compared to other methods. ISO-CHEK meets ASTM D5932-96 and D6561-00 specifications and is an ideal air sampling solution for OSHA’s National Emphasis Program (NEP) on occupational exposure to isocyanates. |
Collection Method | Dual filter cassette; 5-µm PTFE membrane traps aerosol phase, glass fiber filter impregnated with MAMA collects vapor phase |
Sample Flow Rate | 1 L/min |
Sample Time | 15 minutes |
Derivatizing Reagent (filter coating for vapor phase) |
9-(N-methylaminomethyl) anthracene (MAMA) |
Derivatizing Solution (for aerosol phase) |
1-(2-Methoxyphenyl) piperazine (MOPIP) |
Sample Stability | Can be stored at 39.2 F (4 C) for up to 10 days. Store and prepare in solvent-free environments. SKC recommends sample analysis as soon as possible. |
Analysis | Reverse phase HPLC with UV and fluorescence detection |
Quantitation Limit | 0.15 ppb for 2,4-TDI, 2,6-TDI, 1,6-HDI, IPDI, MDI, HMDI monomer 1.5 ppb for 1,6-HDI and MDI oligomers |
Limit of Detection | 0.2 mg/m3 for 2,4-TDI and 2,6-TDI 0.6 mg/m3 for 1,6-HDI 0.3 (UV)/0.08 (FD) mg/m3 ** for MDI |
** | First number is with UV detector, the second is with a fluorescence detector. |
The patented Isocyanate Sampling System is a preloaded three-piece cassette that contains two stages. Stage one contains an untreated PTFE filter to collect the aerosol phase and stage two holds a glass fiber filter impregnated with 9-(N-methylaminomethyl) anthracene (MAMA) for the vapor phase of isocyanates. This system effectively traps and separates the phases at the point of collection and offers many advantages over other methods for sampling isocyanates.
Simultaneous collection and separation of phases at the point
of collection: ISO-CHEK
separates the vapor and aerosol phases at the point of collection
for less time-consuming and more accurate analysis of each phase.
Reagent is stable at room temperature: Loss of
derivatizing reagent was found under ambient conditions
when using other methods.
15-minute sampling time: Isocyanates are sensitizing
agents. Even short 15-minute exposures at high concentrations can lead to
sensitivity in susceptible individuals.
Therefore, short-term sampling provides more meaningful results than the
longer sampling times required by other methods.
No handling precautions: Eliminates inconveniences of impingers.
Principle of Operation
A sample pump draws air through the ISO-CHEK cassette.
Aerosols are trapped on the PTFE filter while gases pass through
to the next
filter. Vapors are trapped on the fiber glass filter impregnated
with MAMA. A chemical reaction occurs on this filter resulting in
the formation
of a highly detectable urea derivative. The PTFE filter is derivatized
in the field by placing it in a supplied jar containing 1-(2 methoxyphenyl)
piperazine reagent (MOPIP). Monomeric and oligomeric phases are
separated by using a reverse phase HPLC column with a UV detector
and fluorescence
detector in series.
Using ISO-CHEK
Simply unplug and connect the cassette to a calibrated
sample pump capable of at least 1 L/min. Take a 15-minute sample
at 1 L/min.
Immediately after sampling, open the cassette, remove the PTFE filter
with forceps,
match the cassette ID number with the reagent jar number, and place
the filter in the prepared reagent jar. The fiber glass filter remains
in the cassette. Replug the cassette, wrap it in foil to protect
the sample from light, and ship the jar and cassette to an ISO-CHEK-certified
laboratory.
ISO-CHEK Isocyanate Sampling System Product Data Bulletin (PDF)
Technical Note: ISO-CHEK — A Comparison of ISO-CHEK Method Parameters and Reagent Stability (PDF)
ISO-CHEK Sampling Protocol
SKC ISO-CHEK Cassettes Laboratory
Reference List
9-(Methylaminomethyl) Anthracene Isophorone Diisocyanate (MAMA-IPDI) (Cat. No. 225-9054)
9-(Methylaminomethyl) Anthracene Methylene bis (4-phenyl isocyanate) (MAMA-MDI)( Cat. No. 225-9062)
9-(Methylaminomethyl) Anthracene Toluene 2,4-Diisocyanate (MAMA-2,4-TDI)( Cat. No. 225-9052)
9-(Methylaminomethyl) Anthracene Toluene 2,6-Diisocyanate (MAMA-2,6-TDI)( Cat. No. 225-9052)