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Table 6 Summary of the derivatisation reagents and suitable detections methods used for sampling isocyanates. The advantages and disadvantages with respective reaction are also summarised together with the matrices used for sampling airborne isocyanates and sampling method used in respective study

From: The role of isocyanates in fire toxicity

Derivatisation reagent Advantages Disadvantages Sample Sampling method Analytical detection Isocyanates Ref
9-(N-Methylaminomethyl)anthracen (MAMA) Structure independent (UV) Light sensitive
Interference with amines and alcohols during derivatisation
Slow reaction rate
Air (breathing zone) In-house made, identical to ISO-CHEK (three stage filter cassette) HPLC-DAD-FL IPDI monomer, HDI monomer, IPDI polyisocyanate, 3 polyisocyanate forms of HDI (Reeb-Whitaker et al. 2012)
Air Impinger HPLC-UV TDI, 2,4-TDA, 2,6-TDA (Persson et al. 1993)
1-(2-methoxyphenyl)-piperazine (1-2MP) Signal independent for electrochemical detection (EC)
Commercially available internal standards
Underestimation of air-levels during long time sampling
Interference with amines and alcohols during derivatisation
Air Impinger HPLC-EC and UV Monomeric (NIOSH 8/15/94 1994)
Air Glass fibre filters TPMLC 2,4-TDI, 2,6-TDI, MDI (Molander et al. 2000)
Air Impinger, ISO-CHECK, IOM samplers (filter based sampling mainly for particles) LC-MS, HPLC-UV-FL, HPLC-PDA UV, HPLC-DAD Mono- and polymeric HDI (Thomasen et al. 2011)
Air Impinger HPLC/MS/MS ICA, aliphatic isocyanates, alkenyl isocyantes, structural isomers (Boutin et al. 2004)
Air (breathing zone) In-house made, identical to ISO-CHEK HPLC IPDI monomer, HDI monomer, IPDI polyisocyanate, 3 polyisocyanate forms of HDI (Reeb-Whitaker et al. 2012)
Personal air, urine Inhalable dust sampling heads, polystyrene containers HPLC, negative ion CI MS MDI, HDI, TDI, IPDI, urinary metabolites of HDI, TDI, MDI, IPDI (Creely et al. 2006)
Air Glass fibre filters, bubblers LC-MS/MS ICA, linear aliphatic isocyanates, alkenyl isocyanates, HDI, IPDI, 2,4-TDI, 2,6-TDI, MDI, PHI (Boutin et al. 2006)
Air Impregnated filters LC-MS/MS 2,4-TDI, 2,6-TDI, NDI, MDI, IPDI, PHI, MIC, ICA (Sennbro et al. 2004)
Air Glass fibre filter in IOM sampler LC-MS/MS HDI based isocyanates (White 2012)
Air IOM sampler, impregnated filter LC/UV/MS MDI (Vangronsveld et al. 2010)
Air Impregnated filters LC/ESI/MS TDI (Mattsson et al. 2008)
1-(9-Antracenylmethyl)piperazine (MAP) Increased chromatographic performance
Quantifies polyisocyanates
Near universal UV response factor
Sensitive UV detection
Compatible with Ph gradient solution
Variable fluorescent yield per NCO
Stability of derivatives uncertain
Not commercially available
MAP artefact peaks
Air Impregnated filters, impinger, or both HPLC-UV-FL Total (NIOSH 2003)
Air Impregnated filters, impinger, or both HPLC-UV-FL Monomeric and oligomeric HDI (Woskie 2004)
Di-n-butylamine (DBA) No interference with amines and alcohols during derivatisation
Can be used in higher concentrations to avoid underestimation
Quantifies isocyanates and amines
Faster reaction times
Commercially available internal standards
Non-routine, expensive analysis
Quantifying polyisocyanates requires standards
Air Impinger and filter LC-MS/MS - (Marand et al. 2005)
Air Impinger HPLC-ESI-MS/MS HDI and its oligomers (Pronk 2006)
Air Impinger LC-MS/MS 2,4-TDI, 2,6-TDI. NDI, MDI, IPDI, PHI, MIC, ICA (Sennbro et al. 2004)
Air Denuder-impactor LC-MS/MS ICA, MIC, EIC, PIC, PHI, HDI, 2,4-TDI, 2,6-TDI, IPDI, MDI (Dahlin et al. 2008b)
1-(2-pyridyl)piperazine (2-PP) Separation of isocyanates (mainly monomers) Polyisocyanates difficult to separate Gaseous and/or aerosol samples drawn from a emission source Multicomponent sampling train HPLC-UV 2,4-TDI, HDI, MDI, MIC (EPA 1997)
Air Glass fibre filters HPLC-UV/FL HDI, 2,4-TDI, 2,6-TDI (Occupational Safety and Health Administration (OSHA) 1989a)
Air Glass fibre filters HPLC-UV/FL MDI (Occupational Safety and Health Administration (OSHA) 1989b)
Air Glass fibre filters HPLC-UV/FL 2,4-TDI, 2,6-TDI (British Standard Institution 2012)
Extracts from solids, soils, filters, foams, collected in impinger solutions   HPLC-DAD/MS 2,4-TDI, 2,6-TDI, HDI, HDI biuret, HDI trimer, 2,4-MDI, 4,4-MDI (US EPA 2004)
Air Filter HPLC-UV/FL Di-isocyanates (Sigma-Aldrich 1994)
Tryptamine Structure independent reaction Slow reaction rate
Matrix interference when using UV detectors
Air Impinger HPLC-FL/EC - (NIOSH 1998)
Air, urine Impinger HPLC-EC/UV HDI (Mirmohammadi et al. 2010)
9-anthracenylmethyl-1-piperazinecarboxylate (PAC) No chromatographic losses of isocyanate species
No response factor variability between isocyanates
Impurities may give high blank of cleavage product
Slow reaction rate
Air Impinger HPLC-UV-FL HDI, PHI, MDI, 2,4-TDI (Roh et al. 2000)
Ferrocenoyl piperazide (FP) Sensitivity No data on reactivity or stability Air Impingers LC-EC/MS - (Seiwert et al. 2004)