scholarly journals Sterilization Induced Changes in Polypropylene-Based Ffp2 Masks

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4107
Author(s):  
Emmanuel Richaud ◽  
Muriel Ferry ◽  
Floriane Carpentier ◽  
Sophie Rouif ◽  
Laurent Cortella ◽  
...  
Keyword(s):  
Size Exclusion ◽  
Gas Chromatography Mass Spectrometry ◽  
Attenuated Total Reflectance ◽  
Beam Irradiation ◽  
Medical Field ◽  
Total Reflectance ◽  
Exclusion Chromatography ◽  
Mode Size ◽  
Γ Rays ◽  
Induced Changes

In the context of the SARS-CoV2 pandemic and because of the surgical and FFP2 mask (equivalent to the American N95 masks) shortages, studies on efficient sterilization protocols were initiated. As sterilization using irradiation is commonly used in the medical field, this method was among those that were evaluated. In this work, we tested irradiation under vacuum and under air (under both γ-rays and e-beams), but also, for acceptance purposes, undertook washing prior to the e-beam irradiation sterilization process. This article deals with the modifications induced by the sterilization processes at the molecular and the macromolecular scales on an FFP2 mask. Fourier transform infrared spectroscopy in attenuated total reflectance mode, size-exclusion chromatography and thermal-desorption–gas chromatography–mass spectrometry were used to characterize possible damage to the materials. It appeared that the modifications induced by the different sterilization processes under vacuum were relatively tenuous and became more significant when irradiation was performed using γ-rays under air.

scholarly journals Size Exclusion Chromatographic Cleanup for GC/MS Determination of Organophosphorus Pesticide Residues in Household and Vehicle Dust

2002 ◽  
Vol 85 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Thomas F Moate ◽  
Matthew Furia ◽  
Cynthia Curl ◽  
Juan F Muniz ◽  
Jianbo Yu ◽  
...  
Keyword(s):  
Organophosphorus Pesticides ◽  
Organophosphorus Pesticide ◽  
Fruit Production ◽  
Size Exclusion ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Size Exclusion Chromatographic ◽  
Tree Fruit ◽  
Exclusion Chromatography

Abstract Size exclusion chromatography (SEC) was used as a cleanup method for the analysis of organophosphorus pesticides in household and vehicle dusts. The pesticides investigated were diazinon, methyl parathion, chlorpyrifos, malathion, phosmet, and azinphosmethyl. These compounds are of interest due to their use in agricultural tree fruit production and/or urban pest control. Pesticides were determined via gas chromatography/mass spectrometry with selected-ion monitoring and cool on-column injection. The lower limit of method validation was 0.20 μg/g. Method limits of detection in dust ranged from 0.012–0.055 μg/g. Dust samples were collected with vacuums from the homes and vehicles of people living and working in a rural agricultural region in the central part of Washington State. The analytes were extracted from the dust by sonication in acetone. The extracts were solvent-exchanged to cyclohexane, frozen, thawed, and centrifuged prior to SEC injection. Following SEC, the eluent was split into 2 fractions, concentrated, and injected on-column into the gas chromatograph. This method represents the first complete publication describing the SEC cleanup of organophosphorus pesticides in dusts. Recoveries of pesticides in dusts ranged from 63.5–110.8 ± 4.9–19.6% over a fortification range of 0.20–10.00 μg/g. This optimized, automated, and reproducible SEC method does not require further treatment or cleanup for trace determination of these organophosphorus pesticides.

The effects of ultraviolet and visible light on common furs: Color changes, photooxidation and the use of Tinuvin 292 as a photoprotectant

2016 ◽  
Vol 30 (1-2) ◽  
pp. 15-33
Author(s):  
Corina E. Rogge ◽  
Anya Shullman
Keyword(s):  
Visible Light ◽  
Uv Radiation ◽  
Light Exposure ◽  
Mechanical Damage ◽  
Attenuated Total Reflectance ◽  
Preventative Treatment ◽  
Total Reflectance ◽  
B Values ◽  
Color Changes ◽  
Induced Changes

Abstract In order to determine the light sensitivities of commonly encountered furs, 17 furs from 12 species were exposed to 1.97 Mlx hours of light from a xenon arc lamp, filtered either to simulate window-filtered daylight or to remove all ultraviolet (UV) radiation. Comparison with coexposed Blue Wools showed that most samples were relatively lightfast (Blue Wool 5 or better), with darker specimens being more lightfast. Examination of the Commission internationale de l'éclairage (CIE) L*a*b* values revealed fading but also other changes: some furs darkened, and other experienced changes in b* values. Removal of UV radiation prevented darkening and usually decreased the magnitude of ΔE76 but did not prevent color changes, and one species exhibited greater change under visible light. Changes in color were accompanied by photooxidation of the keratin of all species as assessed by attenuated total reflectance infrared spectroscopy; the extent of photooxidation was decreased by filtering out UV radiation. Pre-exposure treatment with a spray application of a 1% solution of Tinuvin 292, a hindered amine light stabilizer, offered some protection against both UV and visible light-induced changes. Tinuvin 292 pre-exposure also helped prevent keratin photooxidation and light-induced mechanical damage and thus may be an appropriate preventative treatment when light exposure is unavoidable.

scholarly journals Effect of Artificial Saliva on the Apatite Structure of Eroded Enamel

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Xiaojie Wang ◽  
Boriana Mihailova ◽  
Arndt Klocke ◽  
Stefanie Heidrich ◽  
Ulrich Bismayer
Keyword(s):  
Citric Acid ◽  
Ph Value ◽  
Artificial Saliva ◽  
Additional Treatment ◽  
Attenuated Total Reflectance ◽  
Apatite Structure ◽  
Total Reflectance ◽  
Time Period ◽  
The Individual ◽  
Induced Changes

Citric acid-induced changes in the structure of the mineral component of enamel stored in artificial saliva were studied by attenuated total reflectance infrared spectroscopy as well as complementary electron probe microanalysis and scanning electron microscopy. The results indicate that the application of artificial saliva for several hours (the minimum time period proved is 4 h) leads to slight, partial recovering of the local structure of eroded enamel apatite. However, artificial saliva surrounding cannot stop the process of loosening and breaking of P–O–Ca atomic linkages in enamel subjected to multiple citric acid treatments. Irreversible changes in the atomic bonding within 700 nm thick enamel surface layer are observed after three times exposure for 1 min to aqueous solution of citric acid having a pH value of 2.23, with a 24-hour interval between the individual treatments. The additional treatment with basic fluoride-containing solutions (1.0% NaF) did not demonstrate a protective effect on the enamel apatite structure per se.

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