scholarly journals Properties of Polyhexamethylene Guanidine (PHMG) Associated with Fatal Lung Injury in Korea

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3301
Author(s):  
Dong-Uk Park ◽  
Jihoon Park ◽  
Kee Won Yang ◽  
Ju-Hyun Park ◽  
Jung-Hwan Kwon ◽  
...  
Keyword(s):  
Average Molecular Weight ◽  
Degree Of Polymerization ◽  
Significant Variable ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Polyhexamethylene Guanidine ◽  
Lung Injuries ◽  
Molecular Masses ◽  
Positive Ion ◽  
Reflectron Mode

The use of humidifier disinfectant (HD) has been determined to be associated with lung injuries (HDLI) in Korea. Although HD brands containing polyhexamethylene guanidine (PHMG) oligomers have been found to cause more HDLI compared to brands containing other disinfectants, the physicochemical properties of PHMG have been poorly defined. We aimed to quantify the PHMG dissolved in HD brands, characterize the number-average (Mn) and weight-average (Mw) molecular masses, and identify the polymerization degree of PHMG. Analysis of the PHMG oligomers was performed using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF MS) operated in positive-ion reflectron mode. Eight brands of HD containing PHMG were identified. The PHMG concentrations in these brands ranged from 160 to 37,200 ppm (mean = 3100.9 ppm). Concentration was a significant variable among and within HD brands. The degree of PHMG oligomerization fell within the range of two to four. The averages of Mn and Mw were 517.2 g/mol (range: 422–613 g/mol) and 537.3 g/mol (range: 441.0–678.0 g/mol), respectively. Based on the average molecular weight and the degree of polymerization, the PHMG examined here could be regarded as oligomers, which may be associated with the highest proportion of HDLI being caused by PHMG.

scholarly journals Characteristics of the Molecular Weight of Polyhexamethylene Guanidine (PHMG) Used as a Household Humidifier Disinfectant

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4490
Author(s):  
Dong-Uk Park ◽  
Kee Won Yang ◽  
Jiwon Kim ◽  
Ju-Hyun Park ◽  
So-Yeon Lee ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Health Effects ◽  
Respiratory Health ◽  
Average Molecular Weight ◽  
Degree Of Polymerization ◽  
Flight Mass Spectrometry ◽  
Polyhexamethylene Guanidine ◽  
Lung Injuries ◽  
The Republic ◽  
Oligomeric Compounds

(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.

scholarly journals Demonstration by Mass Spectrometry that Purified Native Treponema pallidum Rare Outer Membrane Protein 1 (Tromp1) Has a Cleaved Signal Peptide

1999 ◽  
Vol 181 (16) ◽  
pp. 5094-5098 ◽  
Author(s):  
David R. Blanco ◽  
Julian P. Whitelegge ◽  
James N. Miller ◽  
Michael A. Lovett
Keyword(s):  
Mass Spectrometry ◽  
Signal Peptide ◽  
Treponema Pallidum ◽  
Spectrometric Analysis ◽  
Laser Desorption Ionization ◽  
Carboxy Terminus ◽  
Ionization Time ◽  
Maldi Tof ◽  
Calculated Mass ◽  
Molecular Masses

ABSTRACT Purified native Tromp1 was subjected to mass spectrometric analysis in order to determine conclusively whether this protein possesses a cleaved or uncleaved signal peptide. The molecular masses of Tromp1, three Treponema pallidum lipoproteins, and a bovine serum albumin (BSA) control were determined by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. The molecular masses of all of the T. pallidum lipoproteins and BSA were within 0.7% of their respective calculated masses. The molecular mass of Tromp1 was 31,510 Da, which is consistent with a signal-less form of Tromp1, given a calculated mass of unprocessed Tromp1 of 33,571 Da, a difference of 2,061 Da (a 6.5% difference). Purified native Tromp1 was also subjected to MALDI-TOF analysis in comparison to recombinant Tromp1 following cyanogen bromide cleavage, which further confirmed the identity of Tromp1 and showed that native Tromp1 was not degraded at the carboxy terminus. These studies confirm that Tromp1 is processed and does not contain an uncleaved signal peptide as previously reported.

Identification of A-Type Proanthocyanidins in Cranberry-Based Foods and Dietary Supplements by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry, First Action Method: 2019.05

2020 ◽  
Author(s):  
Daniel Esquivel-Alvarado ◽  
Emilia Alfaro-Viquez ◽  
Christian G Krueger ◽  
Martha M Vestling ◽  
Jess D Reed
Keyword(s):  
Dietary Supplements ◽  
Principal Component ◽  
Degree Of Polymerization ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tract Infections ◽  
Tof Ms

Abstract Background Cranberry proanthocyanidins (c-PAC) are oligomeric structures of flavan-3-ol units, which possess A-type interflavan bonds. c-PAC differs from other botanical sources because other PAC mostly have B-type interflavan bonds. Cranberry products used to alleviate and prevent urinary tract infections may suffer from adulteration, where c-PAC are replaced with less expensive botanical sources of PAC that contain B-type interflavan bonds. Objective Identifying the presence of A-type interflavan bonds in cranberry fruit and dietary supplements. Methods Thirty-five samples reported to contain A-type PAC (cranberry fruit and cranberry products) and 36 samples reported to contain B-type PAC (other botanical sources) were identified and differentiated using MALDI-TOF MS, deconvolution of overlapping isotope patterns, and principal component analysis (PCA). Results Our results show that both MALDI-TOF MS and deconvolution of overlapping isotope patterns were able to identify the presence of A-type interflavan bonds with a probability greater than 90% and a confidence of 95%. Deconvolution of MALDI-TOF MS spectra also determined the ratio of A-type to B-type interflavan bonds at each degree of polymerization in cranberry fruit and cranberry products, which is a distinguishing feature of c-PAC in comparison to other botanical sources of PAC. PCA shows clear differences based on the nature of the interflavan bonds. Conclusions MALDI-TOF MS, deconvolution of overlapping isotope patterns of MALDI-TOF MS spectra, and PCA allow the identification, estimation, and differentiation of A-type interflavan bonds in cranberry-based foods and dietary supplements among other botanical sources containing mostly B-type interflavan bonds.

scholarly journals Characterizing Oligomeric Hydroxyl Silicon Oils by MALDI-TOF MS With the Pyridine-Modified Matrix

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaoxiao Zhang ◽  
Yan Wang ◽  
Yiqiu Hu ◽  
Cheng Guo ◽  
Chenghua Li ◽  
...  
Keyword(s):  
Silicone Oil ◽  
Average Molecular Weight ◽  
Degree Of Polymerization ◽  
Ionization Efficiency ◽  
Ionization Time ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Silicone Oils ◽  
The Matrix ◽  
Energy Disperse Spectroscopy

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) is a powerful technique for analysis of various polymers, but it is still very difficult to characterize silicone oil due to its poor ionization efficiency. In this work, oligomeric hydroxyl silicone oils were successfully characterized by MALDI-TOF, by using pyridine-modified 2,5-dihydroxylbenzoic acid (DHB) as the matrix. Furthermore, the mixed crystal of DHB and hydroxyl silicone oil was analyzed by scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS), and the analytical results verified that modification with pyridine could remarkably improve the solubility of hydroxyl silicone oil in DHB, leading to the enhancement of its ionization efficiency in MALDI. The analysis of the MS spectra of a series of hydroxyl silicone oils indicated that they tended to be ionized by the attachment with Na+, and the average molecular weight and the degree of polymerization were measured for several oligomeric hydroxyl silicon oils.

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