Optimization of an Interface Chip for Coupling Capillary Electrophoresis with Thermal Lens Microscopic Detection

Uchiyama, Kenji; Tokeshi, Manabu; Hattori, Akihiko; Kitamori, Takehiko

doi:10.2116/analsci.21.49

Cited by 25 publications

(9 citation statements)

References 10 publications

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“…To solve this problem, one way is to introduce the compounds separated by CE into an extended microchannel that has flat surfaces (Otsuka, 2007;Uchiyama et al, 2003Uchiyama et al, , 2005 so that the collinear TLS can be used as usual. This method necessitates fabricating an interface on a chip to connect the capillary and the microchannel, which complicates the detection system and could introduce a dead volume posing potential adverse impacts (such as broadening of the CE peaks, cross contamination between samples) on the measurement.…”

Section: Optical Parametersmentioning

confidence: 99%

Progress in Thermal Lens Spectrometry and Its Applications in Microscale Analytical Devices

Liu

Franko

2014

Critical Reviews in Analytical Chemistry

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Development of thermal lens spectrometry (TLS) as a micro space-compatible photothermal technique and its applications for analysis of different chemical compounds in micro space and particularly in microfluidic systems are reviewed. Theoretical treatment of TLS in micro space has evolved from simply following conventional theory and predictions in macro space to employing a more accurate theory where impacts of the excitation source (Gaussian laser, top-hat incoherent light source, beam divergence, power density), detection scheme (probe beam waist, mode-mismatching degree), sample flow, and sample cell (top/bottom layers, side wall) on the TL signal are included. Noise sources (light sources, sample status, detector) in TLS systems have been analyzed, and optimum pinhole-to-beam radius ratio is suggested for the maximum signal-to-noise ratio. With different excitation light sources from ultraviolet, to visible, to near-infrared regions and coupled with microfluidic devices, these TLS instruments with good temporal and spatial resolution have found many applications for highly sensitive and/or high-throughput detection of chemical or biochemical analytes, for cell imaging or single particle/molecule detection, and for characterization of molecular diffusion in single- or two-phase systems. Prospects and challenges of TLS for future applications in microchemical analysis are discussed.

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Section: Optical Parametersmentioning

confidence: 99%

Progress in Thermal Lens Spectrometry and Its Applications in Microscale Analytical Devices

Liu

Franko

2014

Critical Reviews in Analytical Chemistry

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“…Even smaller volumes can be probed by the use of socalled thermal lens microscopes (TLM). However, the curved surface of the capillary reduces the sensitivity as well as the reproducibility of TLM technique, which requires an interface chip for coupling CE with TLM detection (65,66). This might be the main reason why TLM did not find real application in chemical analysis by CE but was most frequently used for microfluid analysis on microchemical chips and will therefore be discussed in more detail in the next section.…”

Section: Ic-tls and Ce-tlsmentioning

confidence: 99%

Thermal Lens Spectrometric Detection in Flow Injection Analysis and Separation Techniques

Franko

2008

Applied Spectroscopy Reviews

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Recent applications of thermal lens spectrometry in liquid chromatography (HPLC, ion chromatography), capillary electrophoresis, and flow injection analysis are reviewed. Possible effects of performing TLS measurements in flows are discussed initially for different TLS configurations. The emphasis is given to the analysis of real samples, and the performances of various detection schemes in combination with chromatographic techniques and FIA are discussed particularly in terms of sensitivity, sample throughput, and eventual interferences from complex matrices. Coaxial TLS detection with continuous wave excitation is most suitable for detection in HPLC, ion chromatography, and FIA using long-path length cells, when large volume samples are available. On the other hand, transverse or crossed beam TLS was found most suitable for detection in CE where it provides low absolute LODs, which are lowered even further by thermal lens microscopy on microchips, where the capability of detecting a single molecule in the detection volume was demonstrated.

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“…Matching the best LOD expected by UV detection in CE, they demonstrated a 10 28 M LOD for ferroin. Uchiyama et al [63] optimized an interface chip for coupling CE capillaries with TLM detection. They investigated the dependence of number of theoretical plates with respect to the detector location and the channel dimensions by separating several DABSYL-deri- vatized amino acids.…”

Section: Thermal Lens Detectionmentioning

confidence: 99%

Unconventional detection methods for microfluidic devices

2006

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The direction of modern analytical techniques is to push for lower detection limits, improved selectivity and sensitivity, faster analysis time, higher throughput, and more inexpensive analysis systems with ever-decreasing sample volumes. These very ambitious goals are exacerbated by the need to reduce the overall size of the device and the instrumentation -the quest for functional micrototal analysis systems epitomizes this. Microfluidic devices fabricated in glass, and more recently, in a variety of polymers, brings us a step closer to being able to achieve these stringent goals and to realize the economical fabrication of sophisticated instrumentation. However, this places a significant burden on the detection systems associated with microchip-based analysis systems. There is a need for a universal detector that can efficiently detect sample analytes in real time and with minimal sample manipulation steps, such as lengthy labeling protocols. This review highlights the advances in uncommon or less frequently used detection methods associated with microfluidic devices. As a result, the three most common methods -LIF, electrochemical, and mass spectrometric techniques -are omitted in order to focus on the more esoteric detection methods reported in the literature over the last 2 years.

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Optimization of an Interface Chip for Coupling Capillary Electrophoresis with Thermal Lens Microscopic Detection

Cited by 25 publications

References 10 publications

Progress in Thermal Lens Spectrometry and Its Applications in Microscale Analytical Devices

Progress in Thermal Lens Spectrometry and Its Applications in Microscale Analytical Devices

Thermal Lens Spectrometric Detection in Flow Injection Analysis and Separation Techniques

Unconventional detection methods for microfluidic devices

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