Determination of skin-insect repellent icaridin and DEET in human urine using solid-phase extraction and liquid chromatography with tandem mass spectrometry and its application to a sample of Japanese adults.

Nanami NISHIHARA; Tomohiko ISOBE; Mai TAKAGI; Toshiki TAJIMA; Yugo KITAHARA; Mai HAYASHI; Isao SAITO; Satoru WATANABE; Miyuki IWAI-SHIMADA; Jun UEYAMA

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Determination of skin-insect repellent icaridin and DEET in human urine using solid-phase extraction and liquid chromatography with tandem mass spectrometry and its application to a sample of Japanese adults.

Author: Nanami NISHIHARA ¹ ; Tomohiko ISOBE ² ; Mai TAKAGI ² ; Toshiki TAJIMA ¹ ; Yugo KITAHARA ¹ ; Mai HAYASHI ¹ ; Isao SAITO ¹ ; Satoru WATANABE ¹ ; Miyuki IWAI-SHIMADA ² ; Jun UEYAMA ¹
Author Information

1. Department of Biomolecular Sciences, Field of Omics Health Sciences, Nagoya University Graduate School of Medicine.
2. Health and Environmental Risk Division, National Institute for Environmental Studies.
Publication Type:Journal Article
Keywords: DEET; Human biomonitoring; Icaridin; Insect repellent; LC-MS/MS
MeSH: Humans; Solid Phase Extraction/methods*; Tandem Mass Spectrometry/methods*; Adult; Insect Repellents/urine*; DEET/urine*; Young Adult; Male; Japan; Female; Chromatography, Liquid; Biomarkers/urine*; Chromatography, High Pressure Liquid; East Asian People
From:Environmental Health and Preventive Medicine 2025;30():18-18
CountryJapan
Language:English
Abstract: BACKGROUND:Icaridin and DEET are common insect repellents widely used on human skin and clothing (skin-insect repellents [skin-IR]) to repel common pests, such as mosquitoes and biting flies. Novel analytical methods for urinary skin-IR exposure biomarkers that can be effectively applied in epidemiological studies and provide strong evidence related to risk assessment associated with daily exposure are required. In this study, we aimed to develop a method for analyzing the concentrations of icaridin, DEET, and two DEET metabolites N,N-diethyl-3-(hydroxymethyl) benzamide and 3-(diethylcarbamoyl) benzoic acid in human urine.
METHODS:In this analysis, after formic acid-induced acidification of the urine sample, exposure biomarkers were extracted using solid-phase extraction composed of a modified polystyrenedivinylbenzene polymer for reversed phase (hydrophobic) retention. Subsequently, high-performance liquid chromatography-tandem mass spectrometry was performed within 10 min for a separation analysis. The present method was applied to five Japanese adults (aged 20-43 years) who used icaridin or DEET-containing products within a week.
RESULTS:Limits of detection were 0.06-0.11 µg/L. Extraction recoveries were 74%-88%. The intraday and interday variations were 1.5-17.5 and 0.9-15.8% relative standard deviation, respectively. All exposure biomarkers were successfully detected in all five adults. Urinary concentrations of exposure biomarkers reached their maximum values within 15 h after starting to use skin-IR.
CONCLUSIONS:This method was successful in measuring urinary exposure biomarkers of skin-IR, including icaridin and DEET. Moreover, this study presents the first application of biomonitoring of urinary icaridin concentrations after using a commercial product.