Page:NIOSH Manual of Analytical Methods - 5033.pdf/2

 p-NITROANILINE: METHOD 5033, Issue 1, dated 15 August 1994 - Page 2 of 3 EQUIPMENT:

REAGENTS: 1. 2. 3. 4.

p-Nitroaniline, 99%.* Isopropanol, distilled in glass.* Hexane, distilled in glass.* Calibration stock solution, 10 mg/mL: dissolve 0.100 g p-nitroaniline in 10 mL 2-propanol.



See SPECIAL PRECAUTIONS.

1. Sampler: mixed cellulose ester membrane filter (37-mm) and cellulose backup pad (37mm) in a 2-piece filter holder held together by shrinkable band. 2. Personal sampling pump, calibrated, capable of operating 8 h at 1 to 3 L/min, with flexible connecting tubing. 3. HPLC with UV detector (375 nm), silica column (Partisil 10 or equivalent), injector, and electronic integrator. 4. Microliter syringes, various sizes. 5. Volumetric flasks, various sizes. 6. Squat form ointment jars with Teflon gaskets and screw caps. 7. Pipet, 5-mL, with pipet bulb. 8. Tweezers.

SPECIAL PRECAUTIONS: p-Nitroaniline is a toxic agent that may be absorbed through the skin SAMPLING: [3]. It is an explosion risk. Hexane and isopropanol are flammable liquids. 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Remove the front and rear plugs immediately before sampling and attach sampler to personal sampling pump with flexible tubing. Sample at a known flowrate between 1 and 3 L/min and collect a total smaple of 16 to 350 liters of air. 3. Cap the filters, record sample identity and all relevant sample data (duration, ambient temperature and pressure). 4. Prepare blank sample filters by handling in the same manner (open, seal, and transport) as samples except that no air is sampled through the blanks. 5. Ship in suitable container with blanks.

SAMPLE PREPARATION: 6. 7.

Open the filter holder and using tweezers, transfer each mixed cellulose ester filter to an ointment jar. Add 5 mL isopropanol, cap, and swirl the jar to ensure that the filter is thoroughly wetted.

CALIBRATION AND QUALITY CONTROL: 8.

9.

Calibrate daily with at least six working standards. a. Dilute aliquots of p-nitroaniline stock solution with isopropanol in volumetric flasks to encompass the range of interest. b. Prepare calibration graph (peak area vs. µg p-nitroaniline per sample). Determine the recovery (R) of the filters at least once for each lot of filters used in the range of interest. a. Using a microliter syringe, spike 6 filters at each of 3 concentration levels with p-nitroaniline in isopropanol. Allow the filters to dry overnight for solvent evaporation. b. Analyze the spiked filters. Prepare graph of µg recovered vs. µg spiked.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94