Page:NIOSH Manual of Analytical Methods - 5522.pdf/1

 ISOCYANATES 2,4-TDI: CH3C6H3(NCO)2 MW: 174.16 2,6-TDI: CH3C6H3(NCO)2 174.16 MDI: CH2(C6H4NCO)2 250.26 HDI: OCN(CH2)6NCO 168.20 METHOD: 5522, Issue 1

CAS:

584-84-9 91-08-7 101-68-8 822-06-0

5522 RTECS: CZ6300000 CZ6310000 NQ9350000 MO1740000

EVALUATION: PARTIAL

OSHA : Table 1 NIOSH: Table 1 ACGIH: Table 1

PROPERTIES:

Issue 1: 15 May 1996 Issue 2: 15 January 1998 Table 1

SYNONYMS: Table 1 SAMPLING

MEASUREMENT

SAMPLER:

IMPINGER (tryptamine/DMSO; 20 mL)

TECHNIQUE:

HPLC, FLUORESCENCE DETECTOR/ ELECTROCHEMICAL DETECTOR

FLOW RATE:

1 to 2 L/min

ANALYTE:

tryptamine derivatives of isocyanates

VOL-MIN: -MAX: 360 L

15 L @ 35 µg/m3 TDI

INJECTION VOLUME:

25 µL

SHIPMENT:

ship in screw cap vial

MOBILE PHASE:

acetonitrile (40 to 50%)/0.6% sodium acetate buffer (60 to 50%); 1 mL/min

SAMPLE STABILITY:

at least 28 days in dark @ 25 C [1]

COLUMN:

3.9-mm ID x 150 mm stainless steel packed with 10-µm µ-Bondapak C18, or equivalent

BLANKS:

2 to 10 field blanks per set DETECTOR:

BULK:

isocyanate-based oligomers, 1 to 2 mL

fluorescence: ex 275 nm; em 320 nm (electrochemical, +0.80V - confirmatory)

CALIBRATION:

tryptamine derivatives in sampling medium

RANGE:

2,4-TDI: 2,6-TDI: MDI: HDI:

ACCURACY RANGE STUDIED:

not studied

BIAS:

not determined

OVERALL PRECISION ( ACCURACY:

rT

): not determined not determined

0.3 to 14.0 µg/sample 0.6 to 14.0 µg/sample 1.0 to 10.0 µg/sample 0.6 to 20.0 µg/sample [1]

ESTIMATED LOD: 2,4-TDI: 2,6-TDI: MDI: HDI:

0.1 µg/sample 0.2 µg/sample 0.3 µg/sample 0.2 µg/sample [1]

PRECISION ( r):

0.059 MDI: 0.029 0.062 HDI: 0.045 [1]

2,4-TDI: 2,6-TDI:

APPLICABILITY:The working range for TDI is 10 to 250 µg/m3 for a 50-L air sample. This method determines the air concentration of monomers and estimates the concentration of oligomers of specific diisocyanates. It is applicable to vapors and aerosols, such as those produced in a spray-painting operation. The method is not applicable to mixtures of different isocyanates, nor to condensation aerosols from inefficient collection by impingers. NOTE: This method should be used for area sampling only because of the potential exposure hazard from DMSO solutions.

INTERFERENCES:Any substance which elutes with the tryptamine derivatives and fluoresces will interfere with the analysis, e.g., some aromatic diamines. Mobile phase conditions can be adjusted to separate most co-eluting peaks. OTHER METHODS:This method is a modification of a method developed by the Occupational Health Laboratory, Ontario Ministry of Labour [2]. NIOSH Method 5521 is an alternate method for the determination of monomers of 2,4-TDI, 2,6-TDI, MDI, and HDI.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition