Probing the Liquid-Vacuum Interface
Important scientific studies
require precise knowledge
of the unique properties
at the interface between
liquids and solids or at the
liquid surface itself. Analyzing these properties has
proven difficult because
many key analytical instruments are vacuum-based.
In such instruments, liq-
uids normally evaporate
before they can be analyzed. To overcome this problem, scientists have used
sample holders to position liquids for analysis, but such holders are expensive
and designed to fit a single instrument; they also require specially designed cells
for each experiment. Scientists also have tried freezing or drying samples for
analysis in a static state, but always with the question as to whether different
results would have been achieved if the liquid was in its natural state.
Pacific Northwest National Laboratory has developed SALVI: System for
Analysis at the Liquid-Vacuum Interface, a lab-on-a-chip solution, to meet
the needs of such studies. SALVI is a unique, self-contained, portable analytical
tool that, for the first time, enables vacuum-based scientific instruments such as
time-of-flight secondary ion mass spectrometry (TOF-SIMS) to analyze liquid
surfaces in their natural state at the molecular level. Using as little as two drops,
or 100 µL, of liquid and requiring minimal sample preparation and no modifications to scientific instruments, SALVI allows scientists to understand complex
liquids and develop advanced solutions to challenging problems. The depth of
analysis within the sample ranges from a few nanometers to 1 µm, depending
on the instrument supported.
◗ Pacific Northwest National Laboratory, www.pnl.gov
A Fixed Sample Platform
Traditional spectrophotometers have a fixed sample
platform and detection
stage. This arrangement
severely restricts the
number and types of
measurements that can be
undertaken without laborious manual adjustments.
Agilent Technologies Australia (M) Pty Ltd has
introduced the Agilent Cary 7000 Universal Mea-
surement Spectrophotometer (UMS) and Universal
Measurement Accessory (UMA) to aid in this matter.
The Cary 7000 UMS is an advanced spectrophotometer for measuring the
reflection and transmission properties of a material as a function of wavelength.
With six measurement mode capabilities in one integrated system, it offers complete optical characterization of samples in the ultraviolet, visible and near-infrared wavelength ranges in a way not possible before. Independent control of
detector and sample positions enables measurement of both transmittance and
absolute reflectance of a material at any angle and polarization, without moving the sample, and all unattended due to fully automated operation. The Cary
7000 UMS puts the sample at the center of the optical detection process, with an
arm-mounted detector which orbits the sample.
◗ Agilent Technologies Australia (M) Pty Ltd., www.agilent.com
Faster Aircraft Defect
In 2012, aircraft-maker Airbus was ordered to
ground all their A380 superjumbo planes to conduct emergency inspections on each aircraft after
cracks were found in some wing components. The
economic impact of inspection and the resulting
system downtimes affect both the commercial and
military sector, causing downtime that cuts into
both profits and combat readiness. In an effort
to address the apparent shortcomings in modern
inspection technology, Los Alamos National
Laboratory developed an Acoustic Wavenumber
Spectroscopy (AWS) instrument that performs
nondestructive inspection more quickly and easily
than prior spectroscopy solutions.
AWS generates images of hidden structural
properties and/or defects by taking fast, full-field measurements of a structure’s
steady-state response to periodic ultrasonic excitation. AWS’s breakthrough is
in its ability to extract local wave propagation properties by using continuous,
periodic ultrasonic excitation and continuous-scan sensing, which enables noninvasive, high-rate and high-resolution ultrasonic imaging. Taking measurements
of a structure’s relatively high amplitude steady-state response yields significantly
faster scans by avoiding many of the wave-reverberation and signal-to-noise-ratio
issues associated with typical scanned ultrasonic measurements.
◗ Los Alamos National Laboratory, www.lanl.gov
Before the introduction of the Thermo
Scientific Delta Ray Isotope Ratio Infrared Spectrometer, it was all but impossible
to obtain accurate, verifiable real-time or
high-frequency sampling of carbon dioxide
isotope ratio data from samples at their
sources in the field. The size, weight and
complexity of traditional instruments capable of delivering the analytical power needed
for these experiments demanded a conventional laboratory setting. This required samples to be captured and transported to
the laboratory, limiting sampling frequency and adding to the expense. Transportable laser-based instruments couldn’t verify results using reference systems.
However, the Delta Ray spectrometer is a laser-based system that optically
measures isotope ratios. Mid-infrared range radiation generated in a crystal
from two lasers interacts with the sample in an optical chamber. Radiation
is absorbed by carbon dioxide at discrete wavelengths due to the quantum
mechanical rotational and vibrational states. The spectra of the different iso-topologues are shifted to each other and allow their relative abundances to be
easily determined, and hence the isotope ratios. While competitive laser-based
instruments operate in the near-infrared range, the Delta Ray platform was
designed to operate in the mid-infrared range because absorption lines are
about 8,000 times stronger than the NIR. Unique for a field-transportable isotope ratio instrument, the Delta Ray system contains an integrated Universal
Reference Interface (URI) that provides scientists with fully automated referencing and calibration for verifiable measurements.
◗ Thermo Fisher Scientific, www.thermoscientific.com