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Determination of formaldehyde in single cell by capillary electrophoresis with LIF detection
摘要： As a small molecule gas, formaldehyde (FA) is the simplest carbonyl active material and plays an important role in the carbon cycle of metabolism. However, due to the volatile nature of the gas, it is difficult to accurately quantify its content, which limits the study of the mechanism of action in life activities. Thus, an efficient approach to quantitative detection of FA in cells especially in single cell is urgent needed. Nevertheless, no method for quantifying FA in single cell has been reported to date. In this work, a fluorescent probe N-propyl-4-hydrazino-naphthalimide (NPHNA), which has highly desirable attributes and has been applied to living biological samples, was chosen as labeling reagent to detect endogenous FA at single cell level. After optimization of separation conditions, fast baseline separation of the FA derivative N-propyl-4-hydrazone-naphthalimide product (NPHNA-FA) and NPHNA was achieved in about 5 min by capillary electrophoresis with laser-induced fluorescence detection. The detection limit for FA was 5 amol (signal-to-noise ratio of 3). The developed method was validated by the measurements of intracellular levels of FA in single cell.
关键词： Capillary electrophoresis,Endogenous formaldehyde levels,Single cell
更新于2025-09-23 15:22:29
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Au nanoparticle preconcentration coupled with CE-electrochemiluminescence detection for sensitive analysis of fluoroquinolones in European eel ( <i>Anguilla anguilla</i> )
摘要： In this work, a novel method based on gold nanoparticle preconcentration coupled with CE for electrochemiluminescent detection of ciprofloxacin, enrofloxacin, ofloxacin, and norfloxacin in European eels was developed. The addition of gold nanoparticles induced the rapid enrichment of fluoroquinolones, which was simpler than the conventional enrichment approaches such as solid phase extraction and solid-phase microextraction. More than 100 times enrichment was observed after gold nanoparticle aggregation-based preconcentration. The CE-electrochemiluminescent parameters that affected the separation and detection were optimized. Under the optimized conditions, the linear ranges for the four fluoroquinolones were 0.090—8.0 μmol/L with the detection limits between 0.020 to 0.050 μmol/L. The proposed approach showed the advantages of high sensitivity, high selectivity, wide linear range, and low detection limit. It was used to analyze fluoroquinolones in European eel, and the results showed that the developed method can satisfy the detection requirements for fluoroquinolones determination in aquatic products set by China and European Union.
关键词： Capillary electrophoresis,fluoroquinolones,preconcentration,European eel,gold nanoparticle
更新于2025-09-23 15:21:01
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Development of a novel sheathless CE-ESI-MS interface via a CO2 laser ablated opening
摘要： A new and easy to construct sheathless capillary electrophoresis electro spray ionization mass spectrometry (CE-ESI-MS) interface was developed that offers several advantages compared to traditional liquid junction interfaces. The fabrication of the device only requires a CO2 laser engraver that most groups working with microfluids have access to. It only takes a few seconds to create a CO2 laser ablated opening in the bare-fused silica capillaries and the opening can be placed as close as a few mm from the spray tip. The capillary is punctured through a silicone tube such that the opening is directly placed inside this tube, which also serves as a liquid reservoir for the make-up liquid. Electrical contact required for both CE separation and ESI is established via the liquid in this reservoir which is in contact with the electrode of an external high voltage power supply. The developed CE-ESI-MS interface is capable of analysing both small molecules and biomolecules such as peptides in physisorbed PEG polymer brush coated capillaries. Proof-of-principle of the interface was demonstrated by analysing a tryptic digest of BSA. Further, a range of drugs of abuse were also investigated. The examined small molecules (pethidine, nortriptyline, methadone, haloperidol and loperamide) have a quantification limit (LOQ) of 150 ng/mL and a detection limit (LOD) of 40 ng/mL (except for loperamide: LOD = 80 ng/mL). Finally, we used our novel CE-MS interface for the analysis of the Aβ40 peptide. This is a member of the beta-Amyloid peptide family, involved in the development of Alzheimer's disease. A LOQ of 9 μg/mL was obtained for Aβ40, corresponding to 23 fmoles in a sample volume of 11 nL.
关键词： Mass spectrometry,Aβ40,CO2 laser,Sheathless interface,Capillary electrophoresis
更新于2025-09-19 17:13:59
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Capillary Electrophoresis with Laser Induced Fluorescence Detection for Study of the Association of HSP60 Gene Polymorphism with Gouty Arthritis
摘要： Background: Gout arthritis is a common inflammatory arthritis and it poses a major threat to human health. Objective: A method of capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) for the detection of HSP60 gene polymorphism has been developed and applied to the exploration of correlation between gouty arthritis and HSP60 gene polymorphism. Methods: The genomic deoxyribonucleic acid from 59 patients with gouty arthritis and 64 control subjects was extracted and the conservative fragment of HSP60 was amplified. The products were digested with restriction endonuclease NlaIII and then separated and detected by the proposed method. Results: In the case group, there were 7 cases of TT genotype, 29 cases of CC genotype, and 23 cases of CT genotype. In the control group, there were 4 cases of TT genotype, 6 cases of CC genotype, and 54 cases of CT genotype. The detection results of the samples were statistically analyzed by binary logistic regression and Spearman correlation analysis. After adjusting gender, age, and other compounding factors, the TT genotype and CT genotype of the HSP60 gene were found to affect gouty arthritis. Conclusions: When used for gene polymorphism research, the proposed CE-LIF method has the advantages of high efficiency, rapidity, sensitivity, and low sample consumption. A moderate correlation between gouty arthritis and HSP60 genotype distribution was discovered for the first time. Highlights: A new method using CE-LIF for the detection of HSP60 gene polymorphism of 59 patients with gouty arthritis and 64 control subjects in China. The correlation between gouty arthritis and HSP60 gene polymorphism was explored for the first time.
关键词： Gouty arthritis,Capillary electrophoresis,HSP60 gene polymorphism,Laser-induced fluorescence
更新于2025-09-12 10:27:22
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Capillary electrophoresis/visible‐LED induced fluorescence of tryptophan: What's new?
摘要： Tryptophane (Trp) labelled by 3-(4-carboxybenzoyl)-2-quinolinecarboxaldehyde (CBQCA) is very dif?cult to identify using CE and ?uorescence detection (480 nm). Why in this article some mass spectrometry experiments show that Trp is really labelled by CBQCA as Leucine (Leu)? If the maximum of UV absorption ((cid:2)max) is the same between Leu-CBQCA and Trp-CBQCA, the molar extinction coef?cient is around 2 fold higher for Trp-CBQCA. The ?uorescence of the Leu-CBQCA derivative is 50 times more important than for Trp-CBQCA. The addition of 7.5 mM of (cid:3)-cyclodextrin ((cid:3)-CD) was found to be a good mean to improve 2.1 fold the sensitivity of the Trp-CBQCA ?uorescence. Using a buffer containing SDS and (cid:3)-CD in CE, a LOD of 0.7 μM of L-Trp can be reached and the ratio of the intensities between Leu, Isoleucine, Valine, Trp is 100, 21, 15, 1. Negative ESI/MS and MS/MS of the labeled amino acids show that a loss of the carboxylate function takes place. In the presence of two enantiomers of Trp-CBQCA, we have shown that this decarboxylation is not due to the derivatization process in the solution but rather occurs in the source of the mass spectrometer.
关键词： Tryptophan,Capillary electrophoresis,Fluorescence,Biomolecule,3-(4-carboxybenzoyl)-2-quinolinecarboxaldehyde
更新于2025-09-11 14:15:04
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[Methods in Molecular Biology] Microfluidic Electrophoresis Volume 1906 (Methods and Protocols) || Integrated Microfluidic System for Rapid DNA Fingerprint Analysis: A Miniaturized Integrated DNA Analysis System (MiDAS)—Swab Sample-In to DNA Profile-Out
摘要： A fully automated rapid DNA analysis system requires integrating several operational elements performing multiple steps onto one single micro?uidic platform. The functions to include on the micro?uidic platform consist of substrate lysis, lysate DNA extraction, single or multiplexed PCR ampli?cation, amplicon separation, and product readout. Here we describe a fully automated integrated system for forensic short tandem repeat (STR) analysis of reference samples, achieving buccal swab-in and DNA pro?le-out.
关键词： Integration,STR analysis,DNA extraction,Micro?uidics,Multiplexed PCR,Capillary electrophoresis
更新于2025-09-10 09:29:36
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Hydroxypropyl Methacrylate Interaction and Chitosan Coating for Enhanced UV Detection Sensitivity of Colloidal Nanoparticles in Capillary Electrophoresis Analysis
摘要： The binding interactions between silica (SiO2), titania (TiO2) or polymeric nanoparticles with hydroxypropyl methacrylate (HPMA) were investigated for enhancing the ultraviolet (UV) detection sensitivity of these nanoparticles in capillary electrophoresis (CE) analysis. HPMA interacted with colloidal SiO2 nanoparticles, producing a larger CE-UV peak at a slightly shorter migration time. An increase in particle size with HPMA binding was validated using dynamic light scattering. The interaction was selective as HPMA did not interact with TiO2 nanoparticles in aqueous suspension. Chitosan coating of SiO2 or TiO2 nanoparticles produced significantly larger hydrodynamic diameters to further enhance the sensitivity of their UV detection. The analytical technique, which involves coating SiO2 nanoparticles with chitosan first and binding with HPMA next, is novel. It has allowed us to achieve a significant enhancement of 50 folds in detection sensitivity.
关键词： Titania,Colloid,Nanoparticles,Capillary electrophoresis,Chitosan,Hydroxypropyl methacrylate,Silica,Polymer,Dynamic light scattering
更新于2025-09-09 09:28:46