Urushiol Compounds Detected in Toxicodendron-Labeled Consumer Products Using Mass Spectrometry

Abstract

Background: Urushiol, the culprit allergen in Toxicodendron plants such as poison ivy, is an oily mixture of 15 and 17 carbon side chain alk-(en)-yl catechols. Recently, consumer products have been identified that contain Toxicodendron as an ingredient on their label; however, no studies have assessed whether urushiol is indeed present within these products.

Objective: The aim of the study was to determine whether urushiol compounds are present in consumer products labeled as containing Toxicodendron species.

Methods: Gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry were performed on 9 consumer products labeled as containing Toxicodendron species, including topical homeopathic remedies. Single ion monitoring gas chromatography-mass spectrometry was programmed in selective ion mode to detect 3-methylcatechol characteristic fragment ions of alk-(en)-yl catechols after silanization. Similarly, single ion monitoring liquid chromatography-tandem mass spectrometry was programmed to detect 4 urushiol pentadecylcatechols and 5 urushiol heptadecylcatechols using previously reported mass-to-charge ratios.

Results: Gas chromatography-mass spectrometry detected alk-(en)-yl catechols in 67% (6/9) of the products tested. Liquid chromatography-tandem mass spectrometry detected multiple urushiol pentadecylcatechols and heptadecylcatechols in 44% (4/9) of the products tested.

Conclusions: Alk-(en)-yl catechols and multiple urushiols were detected in consumer products listing Toxicodendron species as an ingredient. Clinicians should be aware of these known allergenic ingredients in consumer products.

Figure 1.

Toxicodendron products. Hyland’s Leg Cramps Ointment (A), LUSH Ocean Salt Face and Body Scrub (B), LUSH None of Your Beeswax Lip Balm (C), Bakson’s Rhus Tox Ointment (D), Nelsons Rhus Tox Cream (E), Helios Rhus Tox and Ruta Cream (F), Washington Rhus Tox 6X (G), Washington Rhus Tox 30X (H), and Rhus Tox Skin Test Reagent (I).

Figure 2.

Gas chromatography-mass spectrometry chromatograms of Sea Salt Scrub. A, Total ion chromatogram of 179 and 267 m/z ions. B, An alk-(en)-yl catechol as identified by the 3-MC characteristic select ion ratios. C, A component identified as a non-alk-(en)-yl catechol.