Microextraction techniques with deep eutectic solvents for gas chromatographic analysis: a minireview.

Sample pretreatment is one of the key steps in sample analysis. The design and development of new materials promote advancements in sample pretreatment technology. Deep eutectic solvents (DESs) are a novel material that have been developed in recent years.

A novel phenolphthalein-based fluorescent chemosensor for pyrophosphate detection via an Al displacement approach in real samples and living cells.

Herein, we report a new phenolphthalein appended Schiff base (PASB) as reversible fluorescent sensor for the detection of pyrophosphate (PPi) ions through the metal displacement mechanism. PASB showed sensing exclusively toward Al ions in DMF/HO (v/v = 1/4, pH 5.5) solution, which resulted in a significant fluorescence enhancement at 540 nm.

A phenazine-imidazole based ratiometric fluorescent probe for Cd ions and its application in imaging.

A new phenazine-imidazole based Schiff base (PIS) fluorescent probe has been developed for the ratiometric detection of Cd ions in aqueous media at physiological pH. PIS upon binding with Cd ions shows red shifted fluorescence and thereby, permits ratiometric detection of Cd(II) ions. A detection limit down to 2.

Dicyanoisophorone-based fluorescent probe with large Stokes shift for ratiometric detection and imaging of exogenous/endogenous hypochlorite in cell and zebrafish.

A novel dicyanoisophorone-based red-emissive fluorescence probe (YT) with large Stokes shift (230 nm) was synthesized for rapid (<20 s) and selective detection of hypochlorite ions in nearly 100% aqueous medium. YT responded to hypochlorite ions via the ClO-promoted oxidative deprotection of thioacetal, leading to a red shift in its fluorescence maximum from 590 nm to 640 nm accompanied by naked-eye color change from orange to red. The emission response of the probe toward ClO presented a good linear relationship in the 5-160 μM concentration range, with the LOD of 4.

New colorimetric and fluorometric chemosensor for selective Hg sensing in a near-perfect aqueous solution and bio-imaging.

We report a new 7-nitrobenzo-2-oxa-1, 3-diazolyl (NBD)-based chemosensor containing a piperazine derivative, NBDP, for detection of mercury ions in almost 100% aqueous medium. The chemosensor shows sensing exclusively toward Hg with a switch-on fluorescence response at 543 nm, which could be attributed to the blocking of PET (photo-induced electron transfer) process upon complexation with mercury ions. The molar ratio of Hg(Ⅱ) to NBDP in the complex is 1:1 based on the Job's plot and HRMS studies.

A lysosome-targetable fluorescent probe for real-time imaging cysteine under oxidative stress in living cells.

As an effective lysosomal biomarker for oxidative stress status, cysteine (Cys) plays an important role in lysosomal proteolysis. Herein, we report the first lysosome-targetable fluorescence probe (MCAB) for Cys-selective detection based on nucleophilic addition reaction of sulfhydryl toward a α, β-unsaturated ketone and demonstrate its application to lysosomal-targetable imaging. MCAB is designed based on a α, β-unsaturated ethanoylcarbazole as the fluorophore and the thiols reaction site, and a methylcarbitol unit as a lysosome-targetable group.

A Label-free aptasensor based on Aptamer/NH Janus particles for ultrasensitive electrochemical detection of Ochratoxin A.

In this study, a novel aptasensor based on Aptamer/NH Janus particles is developed for the detection of Ochratoxin A(OTA). By coating gold on the hemispherical surface of the aminated polystyrene particles, Ochratoxin A aptamer is immobilized on the surface of the gold layer for selective identification and the other hemispherical able to bind to Glassy carbon electrode via peptide bond. Under optimum conditions, the sensor exhibited a wide dynamic range of OTA concentration from 1 × 10 nM to 10 nM, and the detection limit is 3.

A phenolphthalein-based fluorescent probe for the sequential sensing of Al and F ions in aqueous medium and live cells.

A novel fluorescent probe, phenolphthalein‑dialdehyde‑(2‑pyridyl) hydrazone (L), for sequentially detecting Al and F in almost 100% aqueous medium was successfully designed and synthesized. The probe offers two binding pockets for Al to form a 1: 2 ligand/metal complex, leading to a significant fluorescence enhancement at 465 nm. Further, the in-situ formed L-Al complex acts as a secondary fluorescent chemosensor for F by quenching the fluorescence of the complex with high selectivity.

Facile preparation of bright orange fluorescent carbon dots and the constructed biosensing platform for the detection of pH in living cells.

Long wavelength (i.e., orange- to red-light) fluorescence emission and functionality are critically longing for the development and applications of carbon dots (CDs) toward biosensor and bioimaging analysis.

[Fluorescent and Magnetic Relaxation Switch Immunosensor for the Detecting Foodborne Pathogen Salmonella enterica in Water Samples].

Fluoroimmunoassay based on quantum dots (QDs) and magnetic relaxation switch (MRS) immunoassay based on superparamagnetic nanoparticles (SMN) were constructed to detect Salmonella enterica (S. enterica) in water samples. In fluoroimmunoassay, magnetic beads was conjugated with S.

[Fluoroimmunoassay and Magnetic Lateral Flow Immunoassay for the Detection of Ractopamine].

A fluoroimmunoassay based on quantum dots (QDs) and a lateral flow immunoassay system based on the magnetic beads (MB) were constructed to detect ractopamine (RAG) in urine samples. The monoclonal antibody (Ab1) against RAC was conjugated with QDs or MB as detector reagent, respectively. They apply a competitive format using an immobilized RAC conjugate and free RAC present in samples.

Down-regulation of aquaporin3 expression by lipopolysaccharide via p38/c-Jun N-terminal kinase signalling pathway in HT-29 human colon epithelial cells.

Aim: To investigate the influence of lipopolysaccharide (LPS) through the p38/c-Jun N-terminal kinase (JNK) signalling pathway on aquaporin 3 (AQP3) expression in HT-29 human colon epithelial cells.

Methods: HT-29 cells were treated with LPS, and then the membrane localisation of AQP3 was examined by immunofluorescence staining. The mRNA and protein expression of AQP3 with LPS exposure was measured by real-time reverse transcription-PCR and Western blot, respectively.

Novel far-visible and near-infrared pH probes based on styrylcyanine for imaging intracellular pH in live cells.

Two novel vis-NIR pH probes based on styrylcyanine with acidic pH response are easily synthesized, which display large Stokes shift and high sensitivity. The significant colocalizations of two probes with LysoTracker Green DND-26 are achieved in C6 cells, suggesting potential application for imaging acidic organelles in live cells.

Aggregation induced ratiometric fluorescence change for a novel boron-based carbazole derivative.

Nanoparticles of a novel boron-based carbazole derivative have been reported. They exhibit efficient green fluorescence, aggregation induced ratiometric fluorescence change and green/blue fluorescent switching to sense VOCs.

Study on the inclusion behavior of p-sulfonatocalix[6]arene with propranolol by spectrofluorometry.

The inclusion interaction between propranolol (PPL) and p-sulfonatocalix[6]arene (SCX6) was investigated by fluorescence and (1)H NMR spectroscopy. Influences of pH, temperature, ionic strength and the concentration of SCX6 were examined in detail. In phosphate buffer solution with pH 7.

A boron-containing carbazole dimer: synthesis, photophysical properties and sensing properties.

A novel boron-containing π-conjugated compound has been synthesized by the introduction of electron-acceptors (dimesitylboron groups) at the 3,3'-positions of a carbazole dimer (electron-donor). The compound possesses excellent electrochemical properties and high fluorescence quantum yields. In addition, is a sensitive fluorescence sensor with remarkable colour changes and the results could be confirmed through theoretical calculations of the compounds and [(n)Bu(4)N](+)(2)[·(F)(2)](2-).

Assemblies of brilliant cresyl violet to DNA in the presence of gamma-cyclodextrin.

The interactions of brilliant cresyl violet (BCV) with herring sperm DNA in gamma-cyclodextrin (gamma-CD) supramolecular system were studied by UV-vis absorption spectroscopy and cyclic voltammetry (CV). Both UV-vis absorption and CV data show that the interaction of BCV with DNA depends on the concentration ratio of BCV to DNA (R), the initial concentration of BCV and gamma-CD. The binding constants of BCV monomer, (BCV)(2) dimer and (BCV)(2)-gamma-CD inclusion complex with DNA are 1.

Synthesis and binding properties of carboxylphenyl-modified calix[4]arenes and cytochrome c.

Two novel carboxylphenyl-modified calix[4]arenes, tetrakis-carboxylphenylcalix[4]arene (TCPC) and 1,3-bis-carboxylphenylcalix[4]arene (BCPC), as well as a corresponding analogue for comparison, tetrakis-phenylcalix[4]arene (TPC), have been synthesized by palladium-catalyzed Suzuki cross-coupling of arylboronic acid and tetrabromocalix[4]arene as a key step. The binding properties of these calix[4]arene derivatives with bovine heart cytochrome c (cyt c) in dimethylformamide (DMF) was investigated by fluorescence spectroscopy. The binding affinity in the order of TCPC>BCPC>>TPC reflects a clear dependence on the number of carboxyl ligating groups attached onto a receptor and suggests the electrostatic force may be the predominant factor driving the complexing process.

Investigation of the association behaviors between biliverdin and bovine serum albumin by fluorescence spectroscopy.

The interaction between biliverdin and bovine serum albumin (BSA) has been studied by steady fluorescence spectroscopy, synchronous fluorescence and resonance light scanning spectra. The binding of biliverdin to BSA quenches the tryptophan residue fluorescence and the results show that both static and dynamic quenching occur together with complex formation. The binding constant and binding sites of biliverdin to BSA at pH 7.

[Study on the interaction between ICT fluorescence probe and bovine serum albumins].

The present article studied the interaction between intramolecular charge transfer fluorescence probe-1-keto-2-(p-dimethylaminobenzal)-tetrohydronaphthalene (KDTN) and bovine serum albumins (BSA). With the concentration of KDTN increasing, the fluorescence of BSA rapidly quenched and the fluorescence peak gradually blue-shifted. The result indicated that they were bound mainly by hydrophobic interaction.

Study on the supramolecular system of 5-(p-hydroxyphenyl)-10,15,20-tris-(4-chlorophenyl)porphyrin with cyclodextrins and its analytical characteristics.

The supramolecular systems of 5-(p-hydroxyphenyl)-10,15,20-tris-(4-chlorophenyl)porphyrin (p-HTClPP) with beta-cyclodextrin (beta-CD), heptakis(2,3,6-tri-O-methyl)-beta-CD (TM-beta-CD), carboxymethyl-beta-cyclodextrin (CM-beta-CD) and sulfurbutylether-beta-CD (SBE-beta-CD) have been investigated by means of absorption, fluorescence and (1)H NMR spectroscopy. The formation of inclusion complexes has been confirmed on the base of changes of spectroscopy properties. "The double reciprocal method" has been used to determine the stoichiometry and the inclusion constants of p-HTClPP with the four cyclodextrins (CDs).

Study for luminescence performance of three methyl xanthine derivatives.

In this paper, the low-temperature phosphorescence (LTP), the low-temperature fluorescence (LTF), the paper substrate room-temperature phosphorescence (PS-RTP) and the room fluorescence (RTF) properties of caffeine (CF), theophylline (TP), and theobromine (TB) are investigated and compared, and some rules are found out: their maximal excitation wavelength and emission wavelength are in the range of 270-300 nm and 395-445 nm, respectively. And the PS-RTP characters of lifetime, polarization and quanta yield are also investigated and compared. It is found that their lifetimes of PS-RTP are all in the level of 0.

Interaction of human serum albumin with bendroflumethiazide studied by fluorescence spectroscopy.

The interactions between bendroflumethiazide (BFTZ) and human serum albumin (HSA) have been studied by fluorescence spectroscopy. Binding constants for drug attachment to the various binding sites of HSA have been measured at different temperatures in physiological buffer solution. The effect of metal ions on BFTZ interaction with HSA was also investigated.

[Study of the effect of aliphatic alcohol on the inclusion interaction of qucertin-cyclodextrin complexes].

The inclusion interaction of qucertin with beta-cyclodextrin and its derivatives was studied by fluorimetry. The formation constants of their inclusion complexes were determined, and the stoichiometry ratio on the formation of the inclusion complexes was determined by equimolar continueous variation method. The effect of aliphatic alcohols with short chains on inclusion process was discussed.

Studies on the spectroscopic behavior of cryptotanshinone, tanshinone IIA, and tanshinone I.

A comparative study on the spectroscopic behavior of cryptotanshinone (CTan), tanshinone IIA (Tan IIA), and tanshinone I (Tan I) has been investigated, including UV-Vis absorption, low temperature phosphorescence (LTP), low temperature fluorescence (LTF), paper substrate-room temperature phosphorescence (PS-RTP), paper substrate-room temperature fluorescence (PS-RTF) and fluorescence in liquid (LF). The effect of pH on the luminescence intensity is discussed. Lifetime and polarization of the LTP and RTP have been examined with phosphorescence lifetime in the range of 0.