5 research outputs found
Miniaturized Thermal-Assisted Purge-and-Trap Technique Coupling with Surface-Enhanced Raman Scattering for Trace Analysis of Complex Samples
It
still remains a great challenge for quantification of trace
analytes in complex samples by surface-enhanced Raman scattering (SERS)
technique due to potential matrix influence or weak SERS responses
of analytes. In this work, a miniaturized thermal-assisted purge-and-trap
(MTAPT) device was designed and developed to eliminate matrix influence
coupled with derivatization method before SERS analysis. The design
of MTAPT chamber was optimized based on quantitative calculation of
its dead volume by computational fluid dynamics simulation. The small
straight chamber was selected as an optimized design with a recovery
of 96.1% for formaldehyde. The practical feasibility of MTAPT was
validated based on four real analytical applications including phenthiol
in industrial water, formaldehyde in flour, sulfion in wastewater,
and methanol in industrial alcohol. The results showed that SERS responses
of all analytes dramatically increased by eliminating sample matrices
after MTAPT process. Phenthiol, formaldehyde, sulfion, and methanol
in real samples could be accurately quantified with recoveries of
80.9ā110.0%, and the analytical results were validated by corresponding
standard methods. The time consumption of MTAPT-SERS for real sample
analysis including sample preparation and determination was within
16 min. It is highly expected that the combination of MTAPT technique
with portable SERS instrument can greatly expand the range of SERS
analysis. The proposed MTAPT-SERS method has high potential for on-site
analysis of complex samples
All-in-One Preparation Strategy Integrated in a Miniaturized Device for Fast Analyses of Biomarkers in Biofluids by Surface Enhanced Raman Scattering
Complex and tedious sample preparation processes have
greatly limited
rapid analyses of biological samples. In this work, an all-in-one
sample preparation strategy based on a miniaturized gas membrane separation/oven
ring enrichment (GMS/ORE) device was developed for efficient surface
enhanced Raman scattering (SERS) analyses of trace biomarkers in biofluid
samples. This strategy integrating gasification separation, liquid
trapping, derivatization SERS activation, and coffee-ring enrichment
could highly promote the efficiency of sample preparation. Meanwhile,
the edges of membranes modified by the hydrophobic-infusing slippery
liquid-induced uniform ācoffee-ringā effect could significantly
improve the sensitivity and stability for SERS quantification. By
adapting proper derivatization approaches to the miniaturized GMS/ORE
pretreatment, the matrix effects in samples could be prominently eliminated,
and clear SERS responses could be obtained for the selective analyses
of target biomarkers. The miniaturized GMS/ORE device was practically
applied for SERS analyses of trace biomarkers in biofluids, including
hydrogen sulfide in saliva samples, creatinine in serum samples, and
sarcosine, creatinine, and dimethyl disulfide in urine samples. Accurate
quantification of all biomarkers was achieved with recoveries of 89.5%ā120.0%,
and the contents found by GMS/ORE-SERS matched well with those found
by corresponding chromatographic methods with relative errors from
ā8.6% to 9.3%. The miniaturized GMS/ORE device with multiple
parallel processing units could simultaneously treat eight samples
in one run with a total analysis time of 40 min. Such an efficient
all-in-one strategy integrated on a miniaturized device possesses
great potential for fast on-site/point-of-care detection in analytical
science and clinical medicine
All-in-One Preparation Strategy Integrated in a Miniaturized Device for Fast Analyses of Biomarkers in Biofluids by Surface Enhanced Raman Scattering
Complex and tedious sample preparation processes have
greatly limited
rapid analyses of biological samples. In this work, an all-in-one
sample preparation strategy based on a miniaturized gas membrane separation/oven
ring enrichment (GMS/ORE) device was developed for efficient surface
enhanced Raman scattering (SERS) analyses of trace biomarkers in biofluid
samples. This strategy integrating gasification separation, liquid
trapping, derivatization SERS activation, and coffee-ring enrichment
could highly promote the efficiency of sample preparation. Meanwhile,
the edges of membranes modified by the hydrophobic-infusing slippery
liquid-induced uniform ācoffee-ringā effect could significantly
improve the sensitivity and stability for SERS quantification. By
adapting proper derivatization approaches to the miniaturized GMS/ORE
pretreatment, the matrix effects in samples could be prominently eliminated,
and clear SERS responses could be obtained for the selective analyses
of target biomarkers. The miniaturized GMS/ORE device was practically
applied for SERS analyses of trace biomarkers in biofluids, including
hydrogen sulfide in saliva samples, creatinine in serum samples, and
sarcosine, creatinine, and dimethyl disulfide in urine samples. Accurate
quantification of all biomarkers was achieved with recoveries of 89.5%ā120.0%,
and the contents found by GMS/ORE-SERS matched well with those found
by corresponding chromatographic methods with relative errors from
ā8.6% to 9.3%. The miniaturized GMS/ORE device with multiple
parallel processing units could simultaneously treat eight samples
in one run with a total analysis time of 40 min. Such an efficient
all-in-one strategy integrated on a miniaturized device possesses
great potential for fast on-site/point-of-care detection in analytical
science and clinical medicine
One-Step Hydrothermal Synthesis of 3D Petal-like Co<sub>9</sub>S<sub>8</sub>/RGO/Ni<sub>3</sub>S<sub>2</sub> Composite on Nickel Foam for High-Performance Supercapacitors
Co<sub>9</sub>S<sub>8</sub>, Ni<sub>3</sub>S<sub>2</sub>, and reduced graphene
oxide (RGO) were combined to construct a graphene composite with two
mixed metal sulfide components. Co<sub>9</sub>S<sub>8</sub>/RGO/Ni<sub>3</sub>S<sub>2</sub> composite films were hydrothermal-assisted synthesized
on nickel foam (NF) by using a modified āactive metal substrateā
route in which nickel foam acted as both a substrate and Ni source
for composite films. It is found that the Co<sub>9</sub>S<sub>8</sub>/RGO/Ni<sub>3</sub>S<sub>2</sub>/NF electrode exhibits superior capacitive
performance with high capability (13.53 F cm<sup>ā2</sup> at
20 mA cm<sup>ā2</sup>, i.e., 2611.9 F g<sup>ā1</sup> at 3.9 A g<sup>ā1</sup>), excellent rate capability, and
enhanced electrochemical stability, with 91.7% retention after 1000
continuous chargeādischarge cycles even at a high current density
of 80 mA cm<sup>ā2</sup>
Uncovering the Role of Crystal Phase in Determining Nonvolatile Flash Memory Device Performance Fabricated from MoTe<sub>2</sub>āBased 2D van der Waals Heterostructures
Although the crystal phase of two-dimensional (2D) transition
metal
dichalcogenides (TMDs) has been proven to play an essential role in
fabricating high-performance electronic devices in the past decade,
its effect on the performance of 2D material-based flash memory devices
still remains unclear. Here, we report the exploration of the effect
of MoTe2 in different phases as the charge-trapping layer
on the performance of 2D van der Waals (vdW) heterostructure-based
flash memory devices, where a metallic 1Tā²-MoTe2 or semiconducting 2H-MoTe2 nanoflake is used as the floating
gate. By conducting comprehensive measurements on the two kinds of
vdW heterostructure-based devices, the memory device based on MoS2/h-BN/1Tā²-MoTe2 presents much better performance,
including a larger memory window, faster switching speed (100 ns),
and higher extinction ratio (107), than that of the device
based on the MoS2/h-BN/2H-MoTe2 heterostructure.
Moreover, the device based on the MoS2/h-BN/1Tā²-MoTe2 heterostructure also shows a long cycle (>1200 cycles)
and
retention (>3000 s) stability. Our study clearly demonstrates that
the crystal phase of 2D TMDs has a significant impact on the performance
of nonvolatile flash memory devices based on 2D vdW heterostructures,
which paves the way for the fabrication of future high-performance
memory devices based on 2D materials