Page:NIOSH Manual of Analytical Methods - 5043.pdf/2

 p-TOLUENESULFONIC ACID: METHOD 5043, Issue 1, dated 15 January 1998 - Page 2 of 4 REAGENTS:

EQUIPMENT:

1. 2. 3. 4. 5.

1. Sampler: 13-mm glass fiber filter in 2-piece filter holder (Swinnex, Millipore Corp., or equivalent). 2. Personal sampling pump, 1 to 3 L/min, with flexible connecting tubing. 3. HPLC, UV detector, 222 nm, integrator, and column (page 5043-1). 4. Vials, 4-mL, with PTFE-lined caps. 5. Graduated cylinder, 1-L, readable to 10 mL. 6. Volumetric flasks, 25- and 10-mL. 7. Syringes, 10-mL, 500-µL, and 100-µL. 8. Ultrasonic water bath. 9. Film, plastic, water resistant. 10. Syringe filters, 3-mm PTFE membranes, 0.45µm pore size, in polypropylene housing. 11. Forceps.

p-Toluenesulfonic acid,* >98% pure. Water, distilled. Acetonitrile,* chromatographic quality. Isopropanol, chromatographic quality. PIC®A, “paired-ion chromatography,” low UV reagent (Waters Corp., or equivalent). PIC®A contains water, tetrabutylammonium hydrogen sulfate, and phosphoric acid. Add entire vial of PIC®A to 1 L of distilled water to make 0.005M solution. 6. Extraction solution: 2% Isopropanol/98% water (v/v). Add 20 mL of isopropanol to distilled water to make 1 L of solution. 7. p-Toluenesulfonic acid calibration stock solution, 4.0 mg/mL. Dissolve 200 mg ptoluenesulfonic acid in extraction solution to make 50 mL of solution.


 * See SPECIAL PRECAUTIONS

SPECIAL PRECAUTIONS: p-Toluenesulfonicacid is highly irritating to the skin and mucous membranes; also, it can cause a potentially explosive reaction of acetic anhydride with water. Acetonitrile is toxic and is a fire hazard (flash point = 12.8 C). Wear protective clothing and work in a well ventilated hood.

SAMPLING: 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Attach the sampler to the personal sampling pump with flexible tubing. 3. Sample at an accurately known flow rate between 1 and 3 L/min for a total sample size of 10 to 1000 L. NOTE: Limit the maximum loading of particulate matter on the filter to approximately 0.5 mg. 4. Seal ends of sampler with plastic film. Ship to laboratory at room temperature.

SAMPLE PREPARATION: 5. 6. 7. 8.

Using the forceps, transfer the 13-mm glass fiber filter to a 4-mL vial. Add 2 mL of the extraction solution to the vial and cap securely. Place the sample vial into an ultrasonic bath and agitate for 10 min. Filter the sample solution through a PTFE membrane syringe filter.

CALIBRATION AND QUALITY CONTROL: 9. Calibrate daily with at least six working standards over the range of interest: 0.04 to 60 µg/mL. a. Prepare working standards over the range of interest. Add a known amount of the calibration stock solution to an aliquot of the extraction solution. b. Analyze together with samples and blanks (steps 12 and 13). c. Prepare calibration graph (peak area or height vs. µg of analyte). 10. Determine recovery (R) at least once for each lot of glass fiber filters in the calibration range (step 9). NIOSH Manual of Analytical Methods (NMAM), Fourth Edition