Abstract
(1) Background: Household humidifier disinfectant (HD) brands containing polyhexamethylene guanidine (PHMG) have been found to cause the most HD-associated lung injuries (HDLIs) in the Republic of Korea. Nevertheless, no study has attempted to characterize the potential association of the health effects, including HDLI, with the physicochemical properties of PHMG dissolved in different HD brands. This study aimed to characterize the molecular weight (MW) distribution, the number-average molecular weight (Mn), the weight-average molecular weight (Mw), and the structural types of PHMG used in HD products. (2) Methods: Quantitative measurements were made using matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry (MALDI-TOF MS). The Mn, Mw, and MW distributions were compared among various HD products. (3) Results: The mean Mn and Mw were 542.4 g/mol (range: 403.0–692.2 g/mol) and 560.7 g/mol (range: 424.0–714.70 g/mol), respectively. The degree of PHMG oligomerization ranged from 3 to 7. The MW distribution of PHMG indicated oligomeric compounds regardless of the HD brands. (4) Conclusions: Based on the molecular weight distribution, the average molecular weight of PHMG, and the degree of polymerization, the PHMG collected from HDLI victims could be regarded as an oligomer. PHMG, as used in household humidifiers, should not be exempted from toxic chemical registration as a polymer. Further study is necessary to examine the association of PHMG oligomeric compounds and respiratory health effects, including HDLI.
Highlights
Many people who use household humidifiers containing chemical-based disinfectants (HDs) in the Republic of Korea (Korea) have developed lung injury, including chemicalassociated asthma, interstitial pneumonitis, and widespread lung fibrosis [1,2,3,4]
We reported the properties of polyhexamethylene guanidine (PHMG), including the concentrations and average molecular weights (MWs) of PHMG dissolved in humidifier disinfectant (HD) product brands using matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry (MALDI-TOF MS)
The distribution of the PHMG MW is presented in intervals of 100 Da (Table 2)
Summary
Many people who use household humidifiers containing chemical-based disinfectants (HDs) in the Republic of Korea (Korea) have developed lung injury, including chemicalassociated asthma, interstitial pneumonitis, and widespread lung fibrosis [1,2,3,4]. These casualties are confirmed to be associated with the use of HDs. From 1994 to 2011, polyhexamethylene guanidine (PHMG), oligo (2-(2-ethoxy) ethoxyethyl guanidinium (PGH), and a mixture of chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) were widely used as HDs in Korea. To the best of our knowledge, there have been no reports of respiratory health problems, including lung injury, caused by chemicals containing
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