Maxxam Develops Analytical Methodology to Meet ACGIH TLVs for Phthalic and Maleic Anhydrides
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Maxxam has developed and validated analytical methodology that can meet recently published ACGIH TLVs for Phthalic anhydride and Maleic anhydride. Analysis is performed using liquid chromatography with tandem mass spectrometry detection (LC/MS/MS).

Both OSHA Method 90 (Phthalic anhydride) and OSHA Method 86 (Maleic anhydride) were adapted to LC/MS/MS analysis in order to meet ACGIH TLVs for TWA and STEL sampling. Sample collection remains based upon OSHA 90 and OSHA 86. Thus, no modifications were made to the sampling media, recommended sampling parameters, or sample preparation procedures specified in the OSHA methods. Maxxam conducted appropriate validation studies at concentrations that correspond to 10% of the TLV under the recommended air sampling conditions for both anhydride compounds. Validation studies included desorption efficiency, retention efficiency under the OSHA specified air sampling conditions, and sample storage stability out to 14 days.

Detailed information is provided below for TLVs, sampling information, and Maxxam’s LC/MS/MS reporting limits for Phthalic anhydride and Maleic anhydride.


Phthalic Anhydride Maleic Anhydride
ACGIH TLV TWA 0.002 mg/m3 0.01 mg/m3
ACGIH TLV STEL 0.005 mg/m3 N/A
OSHA Method 90 86
Sampling Media Veratrylamine-treated GFF (SKC 225-9034) Veratrylamine-treated GFF (SKC 225-9021)
Sampling Conditions 75 L at 1.0 L/min 60 L at 0.5 L/min
Storage Stability Up to 14 days under refrigerated storage conditions
Maxxam LC/MS/MS Reporting Limit 15 ng/sample
(0.0002 mg/m3 for 60 L sample)
60 ng/sample
(0.001 mg/m3 for 60 L sample)


Please note that Maxxam still offers Phthalic and Maleic anhydride testing based upon LC/UV analysis specified in OSHA 90 and OSHA 86. Our reporting limits for LC/UV analysis are 1 µg/sample for Phthalic anhydride and 2 µg/sample for Maleic anhydride. If you wish to submit samples for the lower LC/MS/MS reporting limits, please specify LC/MS/MS analysis on the chain of custody. Please call our Client Services department (800.806.5887) if you have any questions regarding our analytical services. For media orders through Maxxam, visit our web site or call 800.806.5887.

Image source: Wikipedia