---
title: "Phthalic anhydride (85-44-9): exposure limits and sampling"
url: https://analyt-mtc.com/tools/hazard-search/phthalic-anhydride-85-44-9/
lang: en
alternates:
  en: https://analyt-mtc.com/tools/hazard-search/phthalic-anhydride-85-44-9/
  de: https://analyt-mtc.com/de/tools/gefahrstoffsuche/phthalic-anhydride-85-44-9/
---

Hazard search

# Phthalic anhydride

CAS number

85-44-9

Also known as

1,3-Isobenzofurandione

## UK workplace exposure limits

| Limit | Value | Applies to |
| --- | --- | --- |
| 8-hour TWA | 4 mg/m³ |  |
| 15-minute STEL | 12 mg/m³ |  |

### Notations

-   Sen: can cause sensitisation

## Sampling methods

| Method | Sampling | Medium | Analysis | Part numbers |
| --- | --- | --- | --- | --- |
| **MDHS 62** / Aromatic carboxylic acid anhydrides by HPLC / [Method document (opens in a new tab)](http://www.hse.gov.uk/pubns/mdhs/pdfs/mdhs62.pdf) | Active (pump) | 25mm Glass fibre filter with Tenax tube (30/15mg) | HPLC | [225-70A](https://analyt-mtc.com/catalog/product/haz-dust-7204-particulate-monitor/#part-225-70a) / [225-58F](https://analyt-mtc.com/catalog/product/glass-fibre-depth-filters/#part-225-58f) / [226-35](https://analyt-mtc.com/catalog/product/skc-tenax-sorbent-tubes/#part-226-35) |
| **OSHA 90** / Phthalic anhyride by HPLC/UV / [Method document (opens in a new tab)](https://www.osha.gov/sites/default/files/methods/osha-90.pdf) | Active (pump) | Two coated glass fibre filters in cassette | HPLC-UV | [225-7](https://analyt-mtc.com/catalog/product/glass-fibre-depth-filters/#part-225-7) / [225-3LF](https://analyt-mtc.com/catalog/product/aluminium-respirable-dust-cyclone/#part-225-3lf) / [225-1](https://analyt-mtc.com/catalog/product/aluminium-respirable-dust-cyclone/#part-225-1) / [225-9034](https://analyt-mtc.com/catalog/product/skc-coated-treated-filters/#part-225-9034) |

Methods and limits as published by their agencies and summarised by SKC; check the current method and the limit that applies to you before sampling.

Source: [SKC Ltd (UK), Hazard Search, used with SKC's permission (opens in a new tab)](https://www.skcltd.com/hazard-search.html); [SKC Inc. (USA), Sampling Guides, used with SKC's permission (opens in a new tab)](https://international.skcinc.com/sampling-guides/)