Page:NIOSH Manual of Analytical Methods - 5606.pdf/2

 REAGENTS:


 * 1) Isopropanol*, HPLC grade.
 * 2) Acetonitrile*, HPLC grade.
 * 3) Triethylamine (TEA)*, HPLC grade.
 * 4) Water, deionized.
 * 5) Ortho-phosphoric acid*, >85% by weight, ACS grade or better grade.
 * 6) Extraction solvent: 40% isopropanol / 60% acetonitrile (v/v).
 * 7) Thiophanate-methyl stock solution, 10 mg/mL. Prepare in acetonitrile and store in refrigerator.
 * 8) TEA-PO4 preservative. Dissolve 1.4 mL of TEA in 90 mL of deionized water in a 100-mL volumetric flask. Add phosphoric acid to lower pH to 7.0 ± 0.1 as indicated by a calibrated pH meter. Bring volume to 100 mL with water. Keep tightly capped and refrigerated. Solution stable for 12 months.
 * 9) Mobile phase A. Combine 20 mL of n-propanol and 2.8 mL TEA in a 1-L volumetric flask and bring to volume using deionized water. Adjust pH to 7.0 ± 0.1 with phosphoric acid using a pH meter. Final concentrations: 2% n-propanol, 0.02 M TEA-PO4. Degas prior to use.
 * 10) Mobile phase B. Add 20 mL of n-propanol to acetonitrile in a 1-L volumetric flask and bring to volume with acetonitrile. Degas prior to use.

* See SPECIAL PRECAUTIONS.

EQUIPMENT:


 * 1) Sampler: OSHA Versatile Sampler (OVS-2 tube), 13-mm OD inlet, 6-mm OD outlet. Front section contains 270 mg 20/60 mesh XAD-2 sorbent held in place by an 11-mm diameter quartz fiber filter and Teflon® ring, separated from the back section of 140 mg XAD-2 sorbent by a short plug of polyurethane foam. The tube is available commercially.
 * 2) Personal sampling pump: 1 L/min with flexible and inert connection tubing.
 * 3) High performance liquid chromatograph (HPLC) with UV detector.
 * 4) Autosampler capable of 5-µL injections.
 * 5) Analytical column: Phenomenex® Synergi™ µm Hydro-RP 80A (250 × 2.00 mm) or equivalent [see Note 3].
 * 6) Vials, 4-mL and 2-mL, glass with PTFE-lined caps.
 * 7) Syringes, 50-μL ,1-mL, and 5-mL.
 * 8) Volumetric flasks, 5-mL, 100-mL, and 1-L.
 * 9) Syringe filter, PTFE, 4-mm, 0.45-µm pore.
 * 10) Forceps.
 * 11) Small vial/tube rotator.
 * 12) pH meter.
 * 13) Graduated cylinder, 50-mL.
 * 14) Pipettes, glass, disposable, 2-mL.
 * 15) Funnel, plastic.
 * 16) Bagged refrigerant.

SPECIAL PRECAUTIONS: Thiophanate-methyl: Avoid inhaling vapors or dust; avoid skin contact. Wear gloves and suitable clothing when handling pure material. Solvents: Avoid skin contact and open flame. Use in a hood. Phosphoric acid: Avoid skin contact. See Note 1.

SAMPLING:

1. Calibrate each personal sampling pump with representative sampler in line.

2. Connect the sampler to the personal sampling pump with flexible tubing. Place sampler vertically, with the large end down, in the breathing zone.

3. Sample at an accurately known flow rate between 0.1 and 1 L/min for a total sampling volume of up to 480 L. Record volume, and document presence of any known or potential interferences.

4. Cap both ends of the sampler with plastic caps and pack securely with bagged refrigerant for shipment.

SAMPLE PREPARATION:

5. Remove cap from large end. Transfer PTFE retainer ring, filter, and front XAD-2 resin section to a 4-mL vial. Transfer the polyurethane foam divider plug along with the back-up XAD-2 resin bed to a second 4-mL vial.

6. Add 2 mL of extraction solvent to each vial and cap each vial using a PTFE-lined cap.

7. Mix by rotating the vials end-over-end for approximately one hour.