NITRIC OXIDE and NITROGEN DIOXIDE
NO NO2
MW: 30.01 46.01
METHOD: 6014, Issue 1
CAS: 10102-43-9 10102-44-0
RTECS: QX0525000 QW9800000
EVALUATION: FULL
OSHA : 25 ppm NO; C 1 ppm NO 2 NIOSH: 25 ppm NO; 1 ppm STEL NO 2 ACGIH: 25 ppm NO; 3 ppm TWA, 5 ppm STEL NO 2 (1 ppm NO = 1.227 mg/m 3 @ NTP) (1 ppm NO 2 = 1.882 mg/m 3 @ NTP)
PROPERTIES:
6014
Issue 1: 15 August 1994
NO: gas; BP -151.7 °C; vapor density (air=1) 1.0 NO 2: gas; MP -11.2 °C; BP 21 °C; vapor density (air=1) 2.83
SYNONYMS: NO: nitrogen monoxide NO 2: nitrogen peroxide; nitrogen tetroxide SAMPLING SAMPLER:
SORBENT TUBES (oxidizer + 2 triethanolamine-treated molecular sieve)
FLOW RATE: VOL-MIN: -MAX:
NO: 0.025 L/min NO 2: 0.025 - 0.2 L/min 1.5 L 6L
SHIPMENT:
routine
SAMPLE STABILITY:
stable at least 7 days @ 25 °C [1,2]
BLANKS: set
MEASUREMENT TECHNIQUE:
VISIBLE ABSORPTION SPECTROPHOTOMETRY
ANALYTE:
nitrite ion, NO 2-
EXTRACTION SOLUTION:
absorbing solution, 50 mL
WAVELENGTH:
540 nm
CALIBRATION:
standard solutions of NO 2-
RANGE:
3 to 18 µg NO 2- per sample [1]
ESTIMATED LOD:
1 µg NO 2- per sample [3]
PRECISION (Sr):
NO: 0.061 [1]; NO 2: 0.026 [2]
3 to 6 field blanks and 10 media blanks per
ACCURACY RANGE STUDIED: NO: 11-48 ppm [1]; NO 2: 2-12 ppm [2] (1.5-L samples) (3-L samples) BIAS:
NO: 4.1% [1]; NO 2: -2% [2]
ˆ ): NO:0.083 [1]; NO 2:0.063 [2] OVERALL PRECISION (S rT ACCURACY:
NO: ± 20.4%; NO 2: ± 14.6%
APPLICABILITY: The working range for NO is 1 to 50 ppm (1.3 to 61 mg/m 3) for a 1.5-L air sample. The working range for NO 2 is 0.5 to 25 ppm (1 to 47 mg/m 3) for a 3-L air sample. The lower sampling rate for NO is to allow collection of oxidized NO on the back sorbent section. At the lower rate, both NO and NO 2 may be determined simultaneously.
INTERFERENCES: Any compound that reacts with the colorimetric reagents will interfere.
OTHER METHODS: This method is based on that of Willey, et al. [4] and combines S321, S320, and P&CAM 231 in a revised format [3,5]. OSHA methods ID-182 and ID-190 use the same sampler, with measurement by ion chomatography [6].
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
