TOLUENE-2,4-DIISOCYANATE
C9H6N2O 2
MW: 174.16
METHOD: 2535, Issue 2
CAS: 584-84-9
2535
RTECS: CZ6300000
EVALUATION: FULL
OSHA : C 0.02 ppm NIOSH: lowest feasible; carcinogen ACGIH: 0.005 ppm; STEL 0.02 ppm (1 ppm = 7.12 mg/m 3 @ NTP)
PROPERTIES:
Issue 1: 15 August 1987 Issue 2: 15 August 1994
liquid; MP 19.5-21.5 °C; BP 251 °C; density 1.2244 g/mL @ 20 °C; VP ca. 1.3 Pa (0.01 mm Hg; 0.96 mg/m 3) @ 20 °C
SYNONYMS: 2,4-TDI; 2,4-bis(carbonylamino)toluene; 2,4-tolylene diisocyanate
SAMPLING SAMPLER: WOOL
TUBE
WITH
REAGENT-COATED
MEASUREMENT GLASS
(N-[(4-nitrophenyl)methyl]-propylamine on glass wool)
TECHNIQUE:
HPLC, UV DETECTION
ANALYTE:
3,3'-bis[(4-nitrophenyl)methyl]-3,3'dipropyl-1,1'-(4-methyl-1,3-phenylene) diurea (2,4-TDIU)
DESORPTION:
2 mL CH 3OH; ultrasonic bath, 3 min
INJECTION VOLUME:
50 µL
FLOW RATE: 0.2 to 1 L/min VOL-MIN: -MAX:
2 L @ 0.02 ppm 170 L
SHIPMENT:
protect from light
SAMPLE STABILITY:
MOBILE PHASE:
55:45 (v/v) CH 3CN:H 2O with 0.08% Et 3N and 0.16% H 3PO 4; 1.0 mL/min
COLUMN:
25 cm x 4.6 mm; octadecylsilylated silica, 5-µm particle size
DETECTOR:
UV @ 254 nm
CALIBRATION:
standard solutions of 2,4-TDIU in CH 3OH
RANGE:
0.3 to 25 µg 2,4-TDI per sample
at least 14 days @ 25 °C [1]
STABILITY OF REAGENT ON GLASS WOOL: ≤ 7 days @ 25 °C; ≥ 4 weeks @ -21 °C
ACCURACY RANGE STUDIED:
0.039 to 0.53 mg/m 3 [1] (67-L samples)
BIAS:
- 0.5% [1]
ˆ ): 0.033 [1] OVERALL PRECISION (S rT ACCURACY:
ESTIMATED LOD: 0.1 µg 2,4-TDI per sample PRECISION (Sr):
0.067 [1]
± 7.0%
APPLICABILITY: The working range is 0.004 to 0.35 ppm (0.03 to 2.5 mg/m 3) for a 10-L air sample. This method is applicable to isocyanate vapors (2,4-TDI vapor, 2,6-TDI vapor, and hexamethylene diisocyanate (HDI) vapor) [2,3], but not aerosols because of inefficient collection of aerosols and incomplete reaction of aerosol isocyanates with reagent.
INTERFERENCES: The reagent is slightly unstable in the dark at 25 °C. Tailing during HPLC, a result of reagent deterioration, may raise detection limits .
OTHER METHODS: This revises P&CAM 326 [4]. Sangö used similar HPLC conditions [5]. Melcher reviewed methods for isocyanates [6]. Method 5521 (Isocyanates, Monomers), using collection in an impinger, is an alternative method.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
