# Maleic Anhydride (3512)

​MALEIC ANHYDRIDE
C4H2O 3
MW: 98.06
METHOD: 3512, Issue 1
CAS: 108-31-6
3512
RTECS: ON3675000
EVALUATION: FULL
OSHA : 0.25 ppm TWA NIOSH: 0.25 ppm TWA ACGIH: 0.25 ppm TWA (1 ppm = 4.01 mg/m 3 @ NTP)
PROPERTIES:
Issue 1: 15 August 1994
solid; MP 53 °C; d 1.43 @ 22 °C; VP <0.16 mm Hg @ 20 °C; vapor density (air = 1) 3.38
SYNONYMS: 2,5-furandione; cis-butenedioic anhydride; toxilic anhydride
SAMPLING SAMPLER:
BUBBLER (15 mL distilled water)
MEASUREMENT TECHNIQUE:
HPLC, UV DETECTION
ANALYTE:
maleic anhydride
INJECTION VOLUME:
50 µL
FLOW RATE: 0.2 to 1.5 L/min VOL-MIN: -MAX: SHIPMENT:
40 L @ 1.0 mg/m 3 500 L
MOBILE PHASE:
0.5% dicyclohexylamine/0.5% formic acid/25% methanol/74% water, 1.7 mL/min
COLUMN:
µ-Bondapak C 18, 10-µm particle size, 30 cm x 3.9-mm ID or equivalent
DETECTOR:
UV @ 254 nm
CALIBRATION:
standard solutions of maleic anhydride in acetone and distilled water
RANGE:
36 to 1080 µg per sample [1]
plug inlet and outlet with Teflon plugs to prevent spillage during shipment.
SAMPLE STABILITY:
less than 7 days @ 25 °C
BLANKS:
2 to 10 field blanks per set
ACCURACY RANGE STUDIED: BIAS:
0.50 to 2.14 mg/m 3 [1] (340-L samples) - 6.7%
ˆ ): 0.063 [1] OVERALL PRECISION (S rT ACCURACY:
ESTIMATED LOD: 15 µg per sample [2] PRECISION (Sr):
0.035 @ 181 to 723 µg per sample [1]
± 19.0%
APPLICABILITY: The working range is 0.025 to 0.75 ppm (0.1 to 3 mg/m 3) for a 360-L air sample. This method does not distinguish between maleic anhydride and maleic acid, and has limited sample stability [1].
INTERFERENCES: Since maleic anhydride is converted to maleic acid, maleic acid can be considered an interference and will result in a positive bias.
OTHER METHODS: This revises Method P&CAM 302 [2]. Geyer and Saunders reported a modified mobile phase for the determination of maleic anhydride, but used the same sampling technique [3]. A method for the trace analysis of maleic a nhydride in workplace air was published by Kallio [4].
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94 ​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 ​MALEIC ANHYDRIDE: METHOD 3512, Issue 1, dated 15 August 1994 - Page 3 of 3 MEASUREMENT: 11. 12. 13.
Set liquid chromatograph to conditions given on page 3512-1. Inject 50-µL sample aliquot. Measure peak area.
CALCULATIONS: 14. 15.
Read mass, µg, of maleic anhydride (W) found in the sample from the calibration graph. Calculate concentration of maleic anhydride in the actual air volume, V (L), at the sampling site:
EVALUATION OF METHOD: This method was validated over the range 0.50 to 2.14 mg/m 3 at 20 °C and pressure of 757 mm Hg using 360-L samples [1,2]. Overall sampling and measurement precision, SˆrT, was 0.063, with a bias of - 6.7%. Recovery of maleic anhydride was 104% in the range of 181 to 723 µg maleic acid per sample. Sample stability during storage was evaluated at 367 µg per sample. Samples showed an average loss of 13% after seven days of storage at ambient conditions compared to one-day old samples. Refrigeration of samples may retard loss but this has not been experimentally determined.
REFERENCES: [1] [2] [3] [4] [5]
Backup Data Report for Maleic anhydride, prepared under NIOSH Contract 210-76-0123 (1977). NIOSH Manual of Analytical Methods, 2nd. ed., V. 5, P&CAM 302, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 78-175 (1978). Geyer, R. and Saunders, G. A. Determination of Maleic Anhydride in Workplace Air by Reverse Phase HPLC, J. Chromatogr. , 368 (2), 456-458 (1986). Kallio, H. Determination of Trace Concentrations of Maleic Anhydride in Workplace Air, Khig. Zdraveopaz , 32 (3), 86-94 (1989). NIOSH/OSHA Occupational Health Guidelines for Chemical Hazards, Department of Health and Human Services, Publ. (NIOSH) 81-123 (1981), available as GPO Stock
METHOD REVISED BY: M.J. Seymour, NIOSH/DPSE.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94