Page:NIOSH Manual of Analytical Methods - 3512.pdf/2

 MALEIC ANHYDRIDE: METHOD 3512, Issue 1, dated 15 August 1994 - Page 2 of 3 REAGENTS: 1. 2. 3. 4. 5. 6. 7.

8.

EQUIPMENT:

Maleic Anhydride *, ACS reagent grade. Dicyclohexylamine, ACS reagent grade. Formic acid, ACS reagent grade. Methanol, distilled in glass. Acetone, distilled in glass. Water, deionized and distilled. Calibration stock solution, 1 mg/mL. Dissolve 10 mg maleic anhydride in 10 mL acetone. Mobile Phase: Dilute 10 mL of dicyclohexylamine and 10 mL of formic acid to 100 mL with distilled water. Dilute 10 mL of this solution, plus 250 mL methanol, to 1 L with distilled water.

1. Sampler: A 25-mL bubbler with 15 mL distilled water. 2. Personal sampling pump, 0.2 to 1.5 mL/min, with flexible polyethylene or Teflon tubing. 3. Teflon plugs and/or tubing. 4. Liquid chromatograph with a UV detector, recorder, integrator and column (page 3512-1). 5. Syringes, 50-1000-µL. 6. Volumetric flasks, 10-, 100-, and 1000-mL. 7. Pipets, 10- and 15-mL glass, delivery, with pipet bulb. 8. Graduated cylinders, glass, 25-mL.

See Special Precautions

SPECIAL PRECAUTIONS: Maleic anhydride is a powerful irritant. Avoid contact with skin, eyes, and respiratory tract [5].

SAMPLING: 1. 2. 3. 4. 5.

6.

Calibrate each personal sampling pump with a representative sampler in line. Transfer 15 mL distilled water to a bubbler. Connect outlet arm of bubbler to a second empty bubbler and then to the sampling pump. Sample 40 to 500 L of air at an accurately known rate between 0.2 and 1.5 L/min. Seal bubbler for shipment in a suitable container in order to prevent damage during transit. Seal the inlet and outlet of the bubbler stem by connecting a piece of Teflon tubing between them or by inserting Teflon plugs in the inlet and outlet. Collect a bulk sample (ca. 1 g) in a glass vial and ship it separately.

SAMPLE PREPARATION: 7. 8.

Transfer the liquid from the bubbler, quantitatively, to a graduated cylinder. Bring volume to 15 mL with distilled water.

CALIBRATION AND QUALITY CONTROL: 9. 10.

Prepare working standards (20 to 800 µg/10 mL) by adding appropriate aliquots of calibration stock solution to distilled water. Analyze working standards together with samples and blanks (steps 11 through 13). Prepare a calibration graph of area vs. µg of maleic anhydride per 15 mL of sample.

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