scholarly journals Confocal laser-induced fluorescence detector for narrow capillary system with yoctomole limit of detection

Talanta ◽  
2017 ◽  
Vol 165 ◽  
pp. 240-244 ◽  
Author(s):  
Mitchell T. Weaver ◽  
Kyle B. Lynch ◽  
Zaifang Zhu ◽  
Huang Chen ◽  
Joann J. Lu ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Laser Induced Fluorescence ◽  
Confocal Laser ◽  
Fluorescence Detector ◽  
Capillary System ◽  
Narrow Capillary

Heterogeneous Integration of a LASER Induced Fluorescence Detection Device for Point-of-Care Microfluidic Biochemical Analysis

2012 ◽  
Vol 1426 ◽  
pp. 211-222
Author(s):  
Toshihiro Kamei
Keyword(s):  
Fluorescence Detection ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Laser Induced Fluorescence ◽  
Integrated System ◽  
Excitation Source ◽  
Heterogeneous Integration ◽  
Fluorescence Detector ◽  
Optical Components ◽  
Laser Induced Fluorescence Detection

ABSTRACTFluorescence detection is more advantageous than electrochemical detection in terms of high sensitivity, multiplexed detection capability and isolation from analyte. Integration of fluorescence detection, however, is much more difficult. First, it would require heterogeneous integration of various optical components including an excitation source, an optical filter, a lens, a mirror and a detector. Second, most of integrated fluorescence detectors, even though not fully integrated, suffer from high limit of detection (LOD) compared to conventional optical system that consists of discrete optical components. We have reduced laser light scattering in an integrated hydrogenated amorphous Si (a-Si:H) fluorescence detector, significantly improving a limit-of-detection (LOD). The detection platform comprises a microlens and the annular fluorescence detector where a thick SiO2/Ta2O5 multilayer optical interference filter is monolithically integrated on an a-Si:H pin photodiode. With a microfluidic capillary electrophoresis (CE) device mounted on the platform, the integrated system is demonstrated to separate DNA restriction fragment digests with high speed, high sensitivity and high separation efficiency, implying single molecular DNA detection when combined with polymerase chain reaction (PCR). We are now working towards integration of an excitation source to fabricate heterogeneously integrated laser-induced fluorescence detection (LIF) device that would be comprised of an InGaN laser diode, microlenses and the integrated a-Si:H fluorescence detector.

scholarly journals Preparative Method for Isolating α-Zearalenol and Zearalenone Using Extracting Disk

1999 ◽  
Vol 82 (1) ◽  
pp. 90-94 ◽  
Author(s):  
George M Ware ◽  
Yuhong Zhao ◽  
Shia S Kuan ◽  
Allen S Carman
Keyword(s):  
Limit Of Detection ◽  
Solid Phase ◽  
Control Sample ◽  
Preparative Method ◽  
Reversed Phase ◽  
Fluorescence Detector ◽  
Coefficients Of Variation ◽  
Limit Of Quantitation ◽  
Standard Calibration ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method is described for the determination of zearalenol and zearalenone in corn. Zearalenol and zearalenone are extracted from corn with methanol–water (1+1) and cleaned up using a solid-phase extraction (SPE) disk, separatedon a reversed-phase analytical column, and detected with a fluorescence detector. The SPE disk concentrated and cleanly separated zearalenol and zearalenone from sample interferences. Standard calibration curves for zearalenol and zearalenone for the concentration range 25–500 ng/mL were linear. The small extract disk had a column capacity equivalent to 1 g extracted corn. Zearalenol and zearalenone were added at levels ranging from 10 to 2000 ng/g to a control sample that contained no detectable levels of zearalenol and zearalenone. Both toxins were recovered from spiked samples at 106.3 and 103.8%, with coefficients of variation of 7.6 and 13.0%, respectively. The method has an estimated reliable limit of detection and limit of quantitation around 10 and 40 ng/g for each toxin, respectively.

scholarly journals Determination of Tianeptine in Tablets by High-Performance Liquid Chromatography with Fluorescence Detection

2007 ◽  
Vol 90 (3) ◽  
pp. 720-724
Author(s):  
Sevgi Tatar Ulu
Keyword(s):  
Lower Limit ◽  
High Performance ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Linear Calibration ◽  
Fluorescence Detector ◽  
Relative Standard ◽  
Validation Parameters ◽  
Limit Of Quantitation

Abstract A sensitive and selective high-performance liquid chromatographic method has been developed for the determination of tianeptine (Tia) in tablets. The method is based on derivatization of Tia with 4-chloro-7-nitrobenzofurazan (NBD-Cl). A mobile phase consisting of acetonitrile10 mM orthophosphoric acid (pH 2.5; 77 + 23) was used at a flow rate of 1 mL/min on a C18 column. The Tia-NBD derivative was monitored using a fluorescence detector, with emission set at 520 nm and excitation at 458 nm. Gabapentin was selected as an internal standard. Linear calibration graphs were obtained in the concentration range of 45300 ng/mL. The lower limit of detection (LOD) was 10 ng/mL at a signal-to-noise ratio of 4. The lower limit of quantitation (LOQ) was 45 ng/mL. The relative standard values for intra- and interday precision were <0.46 and <0.57%, respectively. The recovery of the drug samples ranged between 98.89 and 99.85%. No chromatographic interference from the tablet excipients was found. The proposed method was validated in terms of precision, robustness, recovery, LOD, and LOQ. All the validation parameters were within the acceptance range. The proposed method was applied for the determination of Tia in commercially available tablets. The results were compared with those obtained by an ultraviolet spectrophotometric method using t- and F-tests.

A handheld laser-induced fluorescence detector for multiple applications

Talanta ◽  
2016 ◽  
Vol 150 ◽  
pp. 135-141 ◽  
Author(s):  
Xiao-Xia Fang ◽  
Han-Yang Li ◽  
Pan Fang ◽  
Jian-Zhang Pan ◽  
Qun Fang
Keyword(s):  
Laser Induced Fluorescence ◽  
Fluorescence Detector

Characterisation of electrochemical immunosensor for detection of viable not-culturable forms of Legionellla pneumophila in water samples

2015 ◽  
Vol 69 (11) ◽  
Author(s):  
Dejla Sboui ◽  
Mina Souiri ◽  
Stephanie Reynaud ◽  
Sabine Palle ◽  
Manel Ben Ismail ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Indium Tin Oxide ◽  
Membrane Filtration ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Angle Measurement ◽  
Electrochemical Immunosensor ◽  
Laser Scanning Microscopy ◽  
Confocal Laser

AbstractLegionella pneumophila may cause a fatal pneumonia in humans known as Legionnaires’ disease (LD). The strategies of L. pneumophila to adapt to and resist stressful environmental conditions include the ability to enter into a VBNC (viable but not culturable) state. The detection of L. pneumophila in environmental samples benefits from the use of standardised methods: for detection and enumeration following membrane filtration (AFNOR T90-431, ISO 11731) and detection and quantification by polymerase chain reaction PCR (AFNOR T90-471, ISO 12869). Culture is hampered by its inability to detect VBNC forms and PCR is unable to discriminate between live and dead bacteria. The present immunosensor was obtained by the immobilisation of a monoclonal anti-L. pneumophila antibody (MAb) on an indium-tin oxide (ITO) electrode by the self-assembled monolayers (SAMs) method using an aminosilane. The immunosensor was characterised by wettability (contact angle measurement), atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM), and electrochemical impedance spectroscopy (EIS). A limit of detection of 10 bacteria per mL was observed on artificial samples.

scholarly journals Estimation of Abamectin Residues Present in Tea: High-Performance Liquid Chromatography Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Madasamy Kottiappan ◽  
Shanmugaselvan Veilumuthu Anandhan ◽  
Selvaganapathi Chandran
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Limit Of Detection ◽  
Black Tea ◽  
Water Mixture ◽  
Fluorescence Detector ◽  
Limit Of Quantification ◽  
Acetone Water ◽  
Sensitive Method

A simple, reliable, and sensitive method was based on high-performance liquid chromatography (HPLC) was developed and validated for the estimation of abamectin residues present in tea. The abamectin residues extracted with acetone-water mixture (70 : 30, v/v) and derivatised with 1-methylimidazole (1-MIM) and trifluoroacetic anhydride (TFAA) were estimated by HPLC using fluorescence detector (FLD). The technique was validated in terms of linearity, precision, recovery, specificity, limit of detection (LOD), and limit of quantification (LOQ). A good linear relationship () was absorbed in the abamectin concentration range from 0.01 to 1.0 μg mL−1. The limit of detection and limit of quantification of the method were 0.01 and 0.02 μg g−1, respectively. The average recoveries of the pesticide from black tea and dried green leaves ranged from 83.3 to 103.8% and 83.8 to 98.0%, respectively.

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