Spotlight 400 ft ir

Fourier transform infrared spectroscopy (FTIR) coupled with a hydrogen-deuterium exchange (HDX) experiment was used to measure changes in keratin bundles due to some treatment. Specifically, dispersion of keratin bundles cause changes in the SC amide II band. SC samples were obtained by tape stripping (AS flon, AS ONE corporation, Japan) from human volar forearms (Japanese males, 30–33 years, N = 3). Before tape stripping, forearm sites were subjected to AE/W treatment using a previously reported technique [25 (link)]. After drying, tape strips were collected and subsequently soaked for 20 min in either a 50 mM (0.7% w/w) aqueous ectoine solution or a 50 mM (1.0% w/w) aqueous HEG solution. They were then allowed to dry under an N₂ atmosphere for 3 min. IR spectra of the dried SC samples were obtained using infrared microspectrometry (Spotlight 400 FT-IR, PerkinElmer, Inc.), and the location of these measurements were noted. The samples were then stored in a desiccator at 25 °C/50% RH under a deuterium/dry N₂ atmosphere for 10 min to induce a gas-phase HDX. SC samples were then measured again at the same spot as previously. All spectra were normalized by the amide I peak, and the degree of HDX was calculated using the amide II band.

Functional
groups and concentrations of specific compounds present within the
supernatant were characterized via a combination of pH testing with
a handheld pH meter, FTIR, and liquid chromatography–mass spectroscopy
(LC–MS).
A drop of the filtered sample supernatant was
placed on a PerkinElmer spotlight 400 FTIR attenuated total reflectance
(ATR) crystal, and absorption was measured between 4000 and 650 cm^–1. To better display absorption characteristics of
the mixed products, DI water was measured, and its spectrum was subtracted
from those of the supernatants.
LC–MS was performed on
a Q-Exactive HF mass spectrometer
with a U3000 chromatography system (Thermo Fisher Scientific); samples
were prepared at 20 μg/mL in 1:1 acetonitrile/water and run
for 30 min at 35 °C through a Waters BEH Amide UHPLC column (2.1
× 100 mm). Mobile phase A was composed of 80:20 MeCN/H₂O with 0.1% NH₄OH, and mobile phase B was identical except
for a 70:30 ratio of MeCN/H₂O. Commercially available standards
for glucose, fructose, galactose, mannose, xylose, ribose, arabinose,
deoxyglucose, deoxyribose, and glutaric acid were analyzed as external
standards, and a ¹³C-labeled glucose compound was run across
all samples as an internal standard.