An underwater gas chromatograph for in-situ analysis of organics in deep-sea.

Background: Deep-sea exploration has emerged as a pivotal area of focus in contemporary geoscience and analysis techniques. For deep-sea analysis, conventional ex-situ water analytical methodologies mean significant economic costs, while also greatly increasing the risk of sample distortion. The solution to this issue lies in in-situ analysis, eliminating the bias from sampling and transportation, and capturing spatial and temporal data simultaneously.

Fast and Sensitive Detection of Anti-SARS-CoV-2 IgG Using SiO@Au@CDs Nanoparticle-Based Lateral Flow Immunoassay Strip Coupled with Miniaturized Fluorimeter.

The development of a novel strategy for the measurement of SARS-CoV-2 IgG antibodies is of vital significance for diagnosis and effect of vaccination evaluation. In this investigation, an SiO@Au@CDs nanoparticle (NP)-based lateral flow immunoassay (LFIA) strip was fabricated and coupled with a miniaturized fluorimeter. The morphology features and particle sizes of the SiO@Au@CDs NPs were characterized carefully, and the results indicated that the materials possess monodisperse, uniform, and spherical structures.

The wavelet transform assisted laser-induced fluorescence detector with high sensitivity.

A wavelet transform assisted laser-induced fluorescence detector with high sensitivity was developed and evaluated. An unconventional microscope objective with a numerical aperture (NA) of 0.5 and a working distance (WD) of 4.

A Miniaturized and Highly Sensitive "Windmill" Three-Channel Fluorescence Detector for Simultaneous Detection of Various Mycotoxins.

A novel "windmill" three-channel light-emitting diode induced fluorescence detector (LED-IF) was proposed to maximize the excitation efficiency and fluorescence collection efficiency. Compared with the typical collinear arrangement, the fluorescence intensity of the three channels was increased by 7.85, 3.

A ratiometric fluorescence probe for bisulfite detection in live cells and meat samples.

The development of reliable probe technology for the detection of bisulfite (HSO) in situ in food and biological samples is contributing significantly to food quality and safety assurance as well as community health. In this work, a responsive probe, EHDI, is developed for ratiometric fluorescence detection of HSO in aqueous solution, meat samples, and living cells. The probe is designed based on the HSO triggered 1,4-addition of electron deficit C = C bond of EHDI.

Facile fluorescence detection of malachite green in fish using molecularly imprinted polymers doped CdTe quantum dots based system.

Malachite green (MG) possesses high toxicity, therefore, the detection of MG in fish tissues is of vital importance. A novel core-shell MIPs doped CdTe quantum dots coated silica nanoparticles (CdTe-MIP/SiO NPs) were synthesized via a simple one-pot strategy. The materials were characterized carefully.

A Simple and Low-cost Preliminary Quantification of Target Membrane Protein in Single Cells.

To study the heterogeneity of target membrane proteins in single cells with cellular integrity, we proposed a simple and low-cost method to obtain the copy number of the membrane proteins. HeLa cells were labeled by FITC affinity bodies specifically targeting HER2 membrane proteins. The immunolabeled HeLa cells were quantified by a laboratory-built laser induced fluorescence detector.

Fabrication and application of molecularly imprinted polymer doped carbon dots coated silica stationary phase.

Facing the difficulties in chromatographic separation of polar compounds, this investigation devotes to developing novel stationary phase. Molecularly imprinted polymers (MIPs) have aroused wide attention, owing to their outstanding selectivity, high stability, and low cost. In this work, a novel stationary phase based on carbon dots (CDs), MIP layer, and silica beads was synthesized to exploit high selectivity of MIPs, excellent physicochemical property of CDs, and outstanding chromatographic performances of silica microspheres simultaneously.

A 96-well plate UV fluorometer based on micro fluorescence detector array and dynamic zero correction algorithm.

A 96-well plate UV fluorometer was developed and evaluated. Eight micro fluorescence detectors close to each other were used as detector array for 8 channels. Each detector employed an UV light emitting diode (LED) as light source and a photodiode (PD) with an amplifier circuit as optoelectronic detector.

A miniaturized hydrogen flame ionization detector based on integrated nozzle assembly and embedded sealing structure.

A modified miniaturized hydrogen flame ionization detector (m-FID) was developed and evaluated. An integrated nozzle assembly was constructed to solve the gas leakage caused by adhesive crack during repeated high-low temperature processes or vibration. An embedded sealing structure was designed to realize the face sealing, thus improving the sealing stability and reliability of the m-FID.

Peltier thermoelectric cooler improves both the signal-to-noise ratio and warm-up time of high-power LED induced fluorescence detector and application to aflatoxins.

High-power LED induced fluorescence detector (HP-LED-IF) suffers from problems of large noise and poor baseline stability. In this study, a Peltier thermoelectric cooler (PTC) was utilized to stabilize the HP-LED junction temperature of a HP-LED-IF to reduce the baseline noise for the first time. Compared with traditional fan cooling, the signal-to-noise ratio was improved to 3.

Enhancement of Chemiluminescence Intensity of S* in Non-premixed Hydrogen Microjet Flame in the Photometric Detector for Sulfur Detection.

A transparent quartz rod (q) placed vertically on top of a non-premixed hydrogen microjet flame in a flame photometric detector (qFPD) was developed and evaluated for sulfur detection. The microjet flame burned around the quartz rod because of Coanda effect, forming an extended downstream flame zone with a relatively low temperature between 550 and 650 °C, which is favorable to the formation of S*. The emission intensity of S* and the signal-to-noise ratio (SNR) of sulfur response were enhanced 2.

Spherical Dichroic Reflector Improves Limit of Detection in Laser-Induced Fluorescence Detection.

A miniature laser-induced fluorescence (mLIF) detector utilizing a novel spherical dichroic reflector (SDR), an unconventional long working distance high magnification objective, an uncommon broadband emission-matched excitation filter pair, and a silicon-based photodiode detector assembly instead of a photomultiplier tube was developed and evaluated. The detection cell was placed at the spherical center of the SDR instead of the regular focus, yielding a 1.8× signal-to-noise ratio (SNR) improvement.

A miniaturized and high sensitive dual channel fluorimeter based on compact collinear optical arrangement.

A miniaturized and high sensitive dual channel fluorimeter was developed and evaluated. It employed collinear optical arrangement, a 365 nm and a 470 nm light emitting diodes (LEDs) as light sources, two photodiodes (PDs) integrated with pre-amplifiers as optoelectronic detectors, and a 12.5 mm × 12.

Aqueous extraction followed by dispersive solid phase extraction with in situ derivatization for the determination of aflatoxins in traditional Chinese medicines.

A green sample preparation method based on aqueous extraction followed by dispersive solid phase extraction (d-SPE) with in situ derivatization (ISD) was developed for the determination of aflatoxins (AFs) in traditional Chinese medicines (TCMs). AFs in TCMs were extracted by alkaline aqueous solution and converted to substituted coumaric acids. Then, mixed-mode anion exchange (MAX) sorbent was used to isolate and enrich the substituted coumaric acids.

A flame photometric detector with a silicon photodiode assembly for sulfur detection.

A flame photometric detector with a silicon photodiode assembly instead of a photomultiplier tube for sulfur detection was developed and evaluated. The photosensitive area of photodiode, the optical design, and band-pass filters, were optimized. It was found that the optimal photosensitive area of the photodiode was 100 (mm), and three focus lenses combined with a broad band-pass filter of 378/52 nm and a QB21 glass yielded the best result.

Quantification of Low Copy Number Proteins in Single Cells.

We have developed an ultrasensitive and highly selective method to quantify low copy number intracellular proteins in a single cell using a low-cost laser-induced fluorescence (LIF) detector and a BV605 fluorescent probe. Active caspase3 proteins in cells were labeled by corresponding antibody-BV605 fluorescent binding, and a cell was injected into a 20 cm × 50 μm i.d.

One step rapid dispersive liquid-liquid micro-extraction with in-situ derivatization for determination of aflatoxins in vegetable oils based on high performance liquid chromatography fluorescence detection.

A rapid dispersive liquid-liquid micro-extraction (DLLME) with in-situ derivatization method for extraction and purification of aflatoxins (AFs) in vegetable oils was developed and evaluated. Oil extract, dichloromethane and trifluoroacetic acid were mixed and injected into water to form a cloudy solution. AFs in the oil were extracted into the numerous liquid droplets (with diameters from a few microns to dozens of microns) of extractant, where derivatization was carried out in situ.

A novel HPLC flow cell integrated UV light emitting diode induced fluorescence detector as alternative for sensitive determination of aflatoxins.

A novel UV light emitting diode induced fluorescence detector (LED-IF) with HPLC flow cell was designed and evaluated for determination of aflatoxins. Ray tracing method was employed to optimize the design of the optical components (such as reshaping thin lens for light source and fluorescence collection), and optical structure, and the geometry of flow cell. An ordinary UV LED with wavelength of 370 nm and radiant power of 5 mW was used as excitation light source.

A compact and low-cost laser induced fluorescence detector with silicon based photodetector assembly for capillary flow systems.

A compact and low-cost laser induced fluorescence (LIF) detector based on confocal structure for capillary flow systems was developed and applied for analysis of Her2 protein on single Hela cells. A low-power and low-cost 450 nm laser diode (LD) instead of a high quality laser was used as excitation light source. A compact optical design together with shortened optical path length improved the optical efficiency and detection sensitivity.

A facile and high sensitive micro fluorimeter based on light emitting diode and photodiode.

A facile and high sensitive micro fluorimeter was developed and evaluated. It employed light emitting diode (LED) as light source, cuvette as detection cell, and photodiode (PD) as optoelectronic detector. Optical and electronic parameters were optimized and demonstrated.

Signal-to-noise ratio enhancement of the compact light-emitting diode-induced fluorescence detector.

To enhance the SNR (signal-to-noise ratio) of the compact light-emitting diode-induced fluorescence detector (LED-FD) ([14]), key parameters including LED and its coupling style, pinhole diameter, calibration, and refractive index matching fluid (RIMF) were optimized. A 20 mA LED with light intensity of 8400 mcd was used as new light source. To optimize pinhole diameter, a theoretical analysis based on a three-dimensional (3D) view of the detection area was proposed and validated experimentally.

Hollow fiber-based liquid-liquid-liquid micro-extraction with osmosis: I. Theoretical simulation and verification.

Osmosis in hollow fiber-based liquid-liquid-liquid micro-extraction (HF-LLLME) was validated and utilized to improve enrichment factor of extraction in this study. When donor phase (sample solution) with higher ion strength than acceptor phase (extraction phase) was used, osmosis was established from acceptor phase, through organic membrane to donor phase. The mass flux expression of analytes across the organic membrane was established based on the convective-diffusive kinetic model, and the kinetic process for HF-LLLME with osmosis was simulated.

A compact and highly sensitive light-emitting diode-induced fluorescence detector for capillary flow systems.

A compact and highly sensitive light-emitting diode-induced fluorescence detector (LED-FD) was constructed and evaluated. The LED excitation beam was restricted by a 200 μm diameter pinhole on a 55 μm thick lighttight film. The LED, excitation filter, pinhole, and capillary flow cell were placed tightly against each other without either optical lens or excitation fiber.