# Nitroaromatic Compounds (2005)

​NITROAROMATIC COMPOUNDS (1) Nitrobenzene: C6H5NO2 MW: (1) 123.11 (2) o-Nitrotoluene: CH3C6H4NO2 (2) 137.14 m-Nitrotoluene: p-Nitrotoluene: (3) 4-Chloronitrobenzene: C6H4ClNO2 (3) 157.56 METHOD: 2005, Issue 3
OSHA : NIOSH: ACGIH:
SYNONYMS:
CAS: (1) 98-95-3 RTECS: (1) DA6475000 (2) 88-72-2 (2) XT3150000 99-08-1 XT2975000 99-99-0 XT3325000 (3) 100-00-5 (3) CZ1050000
EVALUATION: Table 1
Table 1 Table 1 Table 1
2005
PROPERTIES:
Issue 1: 15 August 1990 Issue 3: 15 January 1998
Table 1
(1) Nitrobenzol, oil of mirbane (2) o- Methylnitrobenzene, 2-Methylnitrobenzene, 2-Nitrotoluene m-Methylnitrobenzene, 3-Methylnitrobenzene, 3-Nitrotoluene p-Methylnitrobenzene, 4-Methylnitrobenzene, 4-Nitrotoluene (3) p-Chloronitrobenzene, 1-Chloro-4-nitrobenzene, 4-Nitrochlorobenzene, PCNB, PNCB
SAMPLING
MEASUREMENT
SAMPLER:
SOLID SORBENT TUBE (Silica gel, 150 mg/75 mg)
FLOW RATE:
(1) and (3): 0.01 to 1 L/min; (2) 0.01 to 0.02 L/min
TECHNIQUE:
GAS CHROMATOGRAPHY, FID
ANALYTE:
nitrobenzene, nitrotoluene isomers, 4-chloronitrobenzene
DESORPTION: VOL-MIN: -MAX:
(1) 10 L 150 L
(2) 1L 30 L
(3) 1L 150 L
SHIPMENT:
Routine
SAMPLE STABILITY:
30 days @ 5 C
BLANKS:
2 to 10 field blanks per set
INJECTION VOLUME:
1 mL methanol in ultrasonic bath for 30 minutes 1 µL 250 C 300 C 80 C, 1 min; 8 C/min to 180 C He, 2.5 to 3.0 mL/min
TEMPERATURE -INJECTION: -DETECTOR: -COLUMN: CARRIER GAS: COLUMN:
capillary, 30 m x 0.53-mm ID; µm film crossbonded 5% diphenyl 95% dimethylpolysiloxane, Rtx®-5 Amine or equivalent
ACCURACY RANGE STUDIED:
Table 1
CALIBRATION:
analytes in methanol
BIAS:
Table 1
RANGE:
Table 1
OVERALL PRECISION ( ACCURACY:
rT
): Table 1 Table 1
ESTIMATED LOD: Table 1 PRECISION ( r): Table 1
APPLICABILITY: The working ranges for a 30-L air samples are 0.396 to 1.92 ppm (1.98 to 9.60 mg/m3) for nitrobenzene; 0.346 to 1.73 ppm (1.97 to 9.86 mg/m3) for o-nitrotoluene; 0.344 to 1.72 ppm (1.96 to 9.81 mg/m3) for m-nitrotoluene; 0.303 to 1.52 ppm (1.73 to 8.67 mg/m3) for p-nitrotoluene; and 0.308 to 1.54 ppm (1.98 to 9.92 mg/m3) for 4-chloronitrobenzene [1,2]. INTERFERENCES: Any compounds with retention times similar to the analytes of interest will interfere. During sampling, high humidity may greatly decrease breakthrough volume. OTHER METHODS:This method is an update of NMAM 2005, Nitrobenzenes, issued 15 August 1994, which combined and replaced methods S217, S218, and S223 [2,3].
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition ​NITROAROMATIC COMPOUNDS: METHOD 2005, Issue 3, dated 15 January 1998 - Page 2 of 5 EQUIPMENT:
REAGENTS:
1. Sampler: glass tube, 7 cm long, 6-mm OD, Methanol, HPLC chromatographic grade. 4-mm ID, flame-sealed ends with plastic Nitrobenzene*, reagent grade. caps, containing two sections (front=150 mg; o-,m-,p-nitrotoluene isomers,* reagent grade. back=75 mg) of 20/40 mesh silica gel 4-chloronitrobenzene*, reagent grade. separated by a 2-mm urethane foam plug. Calibration stock solution, 500 µg/mL. Prepare A silylated glass wool plug precedes the front each analyte in methanol. section and a 3-mm urethane foam plug 6. Helium, purified and filtered. follows the back section. 7. Hydrogen, purified and filtered. 2. Personal sampling pump, 0.01 to 1 L/min, 8. Air, purified and filtered. with flexible connecting tubing. 3. Gas chromatograph, FID, integrator and column (page 2005-1).
4. Autosampler vials, glass, 2-mL, with PTFElined crimp caps. 5. Volumetric flasks, 10-mL. 6. Pipets, 5-mL and 3-mL, with pipet bulb. 7. Syringes, 10-µL, 100-µL, and 1-mL. 8. Ultrasonic bath. 1. 2. 3. 4. 5.
SPECIAL PRECAUTIONS: These analytes are severe poisons and irritants. Prevent contact with eyes, skin, or clothing by wearing eye protection, chemically resistant gloves, and a lab coat. Avoid inhalation. Nitrobenzene and m-nitrotoluene are absorbed through contact with skin and can cause methemoglobinemia [5,6]. 4-Chloronitrobenzene is a carcinogen. Methanol is highly flammable.
SAMPLING: 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Break the ends of the sampler immediately before sampling. Attach sampler to personal sampling pump with flexible tubing. 3. Sample at an accurately known flow rate between 0.01 and 0.2 L/min for nitrotoluene isomers. Use a flow rate of 1 L/min or less for nitrobenzene and 4-chloronitrobenzene. Note the maximum and minimum sample volumes on page 2005-1. 4. Cap both ends of the sampler. Pack securely for shipment.
SAMPLE PREPARATION: 5. Place the front (include the glass wool plug) and back sorbent sections of each sample tube in separate vials. Discard the foam plugs. 6. Add 1.0 mL of methanol to each vial. Attach crimp cap securely to each vial. 7. Allow to desorb 30 min in an ultrasonic bath.
CALIBRATION AND QUALITY CONTROL: 8. Calibrate daily with at least six working standards to cover the analytical range of the method. If necessary, additional standards may be added to extend the calibration curve. a. Add known amounts of calibration stock to methanol in 10-mL volumetric flasks and dilute to the mark. b. Analyze together with samples and blanks (steps 11 and 12). c. Prepare calibration graph (peak area vs µg analyte). 9. Determine desorption efficiency (DE) at least once for each lot of silica gel used for sampling in the calibration ranges (step 8). NIOSH Manual of Analytical Methods (NMAM), Fourth Edition ​NITROAROMATIC COMPOUNDS: METHOD 2005, Issue 3, dated 15 January 1998 - Page 3 of 5 a. b.
Prepare three tubes at each of five levels plus three media blanks. Inject a known amount of calibration stock solution directly onto the front sorbent section of each silica gel tube with a microliter syringe. c. Allow the tubes to air equilibrate for several minutes, then cap the ends of each tube and allow to stand overnight. d. Desorb (steps 5 through 7) and analyze together with standards and blanks (steps 11 and 12). e. Prepare a graph of DE vs µg analyte recovered. 10. Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration graph and DE graph are in control.
MEASUREMENT: 11. Set gas chromatograph according to manufacturer’s recommendations and to conditions given on page 2005-1. Inject a 1-µL sample aliquot manually using the solvent flush technique or with an autosampler. NOTE: If peak area is above the linear range of the working standards, dilute with methanol, reanalyze and apply the appropriate dilution factor in the calculations. 12. Measure peak areas.
CALCULATIONS: 13. Determine the mass, µg (corrected for DE) of analyte found in the sample front (W f) and back (Wb) sorbent sections, and in the average media blank front (B f) and back (Bb) sorbent sections. NOTE: If Wb > Wf/10, report breakthrough and possible sample loss. 14. Calculate concentration, C, of analyte in the air volume sampled, V(L):
C
NOTE: µg/mL
(Wf
Wb V
Bf
Bb)
, mg/m 3
mg/m3
EVALUATION OF METHOD: The update of this method included the use of capillary column chromatography that lowered the LOD/LOQ values, a lower 5-level desorption efficiency study, and a 30-day storage stability study for each analyte [1]. The method evaluation data for these compounds are listed in Table 2. Methods S217, Nitrobenzene, and S218, 4-nitrochlorobenzene, were initially issued on November 21, 1975 [4]. Method S223, o-nitrotoluene was issued on December 19, 1975 [4]. The analytesm-nitrotoluene and p-nitrotoluene were added on May 15, 1984 [3]. In the original method development work, sample tube capacity, or breakthrough, was determined as 5% of the generated atmosphere concentration as measured in the effluent of the sample tubes. Capacity was measured at >2.8 mg/sample for nitrobenzene; >2.5 mg/sample for nitotoluene isomers; and >2.2 mg/sample for 4-chlorobenzene [2.]
REFERENCES: [1] Pendergrass SM [1997]. Backup data report for nitroaromatic compounds method development. Cincinnati, OH: National Institute for Occupational Safety and Health, DPSE/NIOSH (unpublished December). [2] NIOSH [1977]. Documentation of the NIOSH Validation Tests, S217, S218, and S223, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-185. [3] NIOSH [1994]. m-Nitrotoluene and p-Nitrotoluene: Method 2005. In: Eller PM, Cassinelli ME, eds. th NIOSH Manual of Analytical Methods, 4 ed. Cincinnati, OH: U.S. Departmentof Health and Human NIOSH Manual of Analytical Methods (NMAM), Fourth Edition ​NITROAROMATIC COMPOUNDS: METHOD 2005, Issue 3, dated 15 January 1998 - Page 4 of 5 Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-113. [4] NIOSH [1978]. Nitrobenzene: Method S217;p-Chloronitrobenzene: Method S218; and Nitrotoluene: Method S223. In: Taylor DG, ed. NIOSH Manual of Analytical Methods,nd2 ed., Cincinnati, OH: U.S. Department of Health, Education, and Welfare, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, Publ. (NIOSH) 77-157-C. [5] NIOSH [1977]. Occupational diseases, a guide to their recognition, revised ed., 235-238, 280-281, U.S. Department of Health, Education, and Welfare, DHEW (NIOSH) Publication No. 77-157-C. [6] NIOSH [1981]. NIOSH/OSHA Occupational Health Guidelines for Chemical Hazards, Nitrobenzene, pNitrochlorobenzeneand Nitrotoluene, U.S. Department of Health and Human Services, Publ. (NIOSH) 81-123.
METHOD WRITTEN BY: Stephanie M. Pendergrass, NIOSH/DPSE
TABLE 1. GENERAL INFORMATION TWA Chemical
OSHA NIOSH ACGIH
Physical Properties
Method Evaluation
Nitrobenzene
1 ppm (5.0 mg/m3) (skin) Colorless oily liquid, almond odor; 1 ppm (5.0 mg/m3) (skin) d=1.196 g/mL @ 20 C; MP 6 C; BP 2101 ppm (5.0 mg/m3) (skin) 211 C; VP=37 Pa (0.30 mm Hg) @ 20C
Full
o-Nitrotoluene
5 ppm (28.5 mg/m3) (skin) 2 ppm (11.7 mg/m3) 2 ppm (11.7 mg/m3)
yellowish liquid; d=1.163 g/mL @ 20C; MP -4 C; BP 222 C; VP=20 Pa (0.15 mm Hg) @ 20 C
Full
m-Nitrotoluene
5 ppm (28.5 mg/m3) 2 ppm (11.7 mg/m3) 2 ppm (11.7 mg/m3)
liquid; d=1.157 g/mL @ 20 C; MP 16 C; BP 232 C; VP=20 Pa (0.15 mm Hg) @ 20 C
Partial
p-Nitrotoluene
5 ppm (28.5 mg/m3) 2 ppm (11.7 mg/m3) 2 ppm (11.7 mg/m3)
yellow crystals; d=1.163 g/mL @ 20C; MP 52 C; BP 238 C; VP=17 Pa (0.12 mm Hg) @ 20 C
Partial
yellow crystals; d=1.298 g/mL @ 20C; MP 83 C; BP 242 C; VP=28 Pa (0.2 mm Hg) @ 30 C
Partial
0.16 ppm (1.03 mg/m3) Ca* 0.1 ppm (0.644 mg/m3)
4-Chloronitrobenzene
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition ​NITROAROMATIC COMPOUNDS: METHOD 2005, Issue 3, dated 15 January 1998 - Page 5 of 5
TABLE 2. METHOD SUMMARY Chemical
Range Studieda (mg/m3)
Nitrobenzene
rT
Bias Accuracy (±%)
Analytical Range
LOD
(µg/sample)
(µg/sample)
r
Desorption 30-Day Efficiency Storage (%) (% Rec)
1.98 to 9.60 0.0590 0.0186
12.3
2 to 598
0.6
0.012
98.7
100.2
o-Nitrotoluene 1.97 to 9.86 0.0142 -0.120
21.1
3 to 582
0.8
0.028
98.2
101.2
3 to 579
1.0
0.042
97.5
99.4
9 to 511
2.6
0.061
96.9
99.4
4-Chloro1.98 to 9.92 0.1034 0.0869 27.3 8 to 595 2.5 0.063 nitrobenzene a 30-L air sample b Not determined c Exceeds the NIOSH accuracy criterion of ± 25% at the 95% confidence level
100.3
97.6
m-Nitrotoluene not studied
b
nd
nd
nd
p-Nitrotoluene not studied
nd
nd
nd c
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition