Correlation capillary zone electrophoresis, a novel technique to decrease detection limits

Moolen, J.N. van der; Louwerse, D.J.; Poppe, H.; Smit, H.C.

doi:10.1007/bf02269896

Cited by 33 publications

(37 citation statements)

References 27 publications

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“…In this technique, multiple sample injection according to a Hadamard code sequence derived from a Hadamard matrix was employed for CZE separation. Other studies involving crosscorrelation electrophoresis [14][15][16], Shah convolution Fourier transform electrophoresis [17][18][19], and modified HT microchip electrophoresis [20] have also been reported as techniques for improving the sensitivity in CZE using analogous mathematical transformations.…”

Section: Introductionmentioning

confidence: 97%

Application of Hadamard transformation to MEKC

2007

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The Hadamard transform (HT) technique, which permits the S/N in CE to be improved, was applied to MEKC. Multiple sample injection of fluorescent analytes according to a Hadamard code sequence was performed using an optically gated sample injection technique, in which a sample plug was produced based on photodegradation by irradiation with an intense laser beam. The capillary and reservoirs were filled with a sample solution containing buffer components and SDS as a pseudostationary phase. A preliminary study confirmed that fluorescein ion could be photobleached in the presence of SDS. The optically gated sample injection technique was then applied to multiple sample injection, based on a Hadamard matrix. The S/N in the electropherogram obtained by HT-MEKC was improved substantially compared to that obtained by a single injection method. When the technique was applied to the separation of several amino acids labeled with FITC, the S/N ratio for each amino acid was enhanced, without any evidence of degradation in separation resolution. Moreover, HT-MEKC was applied to the analysis of amino acids contained in a Japanese beverage, resulting in improved S/Ns for the amino acids.

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Section: Introductionmentioning

confidence: 97%

Application of Hadamard transformation to MEKC

2007

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“…cross-correlation CE [4][5][6] or Hadamard transform CE [7,8], both of which measure several signals simultaneously, yielding an electropherogram with improved signal-to-noise).…”

Section: Introductionmentioning

confidence: 98%

Thermal marks as a signal processing aid for a portable capillary electropherograph

2011

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The interpretation of raw signals in capillary CE can be challenging if there are unknown peaks, or the signal is corrupt due to baseline fluctuations, EOF velocity drift, etc. Signal processing could be required before results can be interpreted. A suite of signal processing algorithms has been developed for CE data analysis, specifically for use in field experiments for the detection of nerve agents using portable CE instruments. Everything from baseline correction and electropherogram alignment to peak matching and identification is included in these programs. Baseline correction is achieved by interpolating a new baseline according to points found using all local extremes, by applying an appropriate outliers test. Irreproducible migration times are corrected by compensating for EOF drift, measured with the aid of thermal marks. Thermal marks are small disturbances in the capillary created by punctual heating that move with the velocity of EOF. Peaks in the sample electropherogram are identified using a fuzzy matching algorithm, by comparing peaks from the sample electropherogram to peaks from a reference electropherogram.

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“…Correlation detection for CZE similarly utilizes a pseudorandom sequence of injections for improvements in S/N. Van der Moolen et al performed UV detection with correlation CZE by microfabricating an injection device in order to perform rapid sequential electrokinetic injections into a conventional capillary [10]. This device was micromachined on a glass sheet with dry and wet etching techniques to design the channels where the sample and buffer solutions were injected.…”

Section: Introductionmentioning

confidence: 98%

Hadamard transform CE-UV detection for biological samples

et al. 2005

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A Hadamard transform-capillary electrophoresis-UV (HT-CE-UV) detection technique is described for the analysis of biological samples. Pseudorandom injections of sample and buffer according to a simplex matrix obtained from the corresponding Hadamard matrix is performed with conventional capillaries. Alternating injections are achieved with a novel capillary "T" connector created by drilling conventional capillary dimensions through a 1-cm diameter polycarbonate disc. This connector design coupled with a switching system allows for rapid, electrokinetic injections of solution into alternating sample and buffer capillary arms for UV detection. The standard mixtures of nitric oxide (NO) metabolites, nitrite and nitrate, dissolved in physiological saline solution are injected into the separation capillary according to an 83-element injection sequence to obtain a signal-to-noise ratio (S/N) enhancement of ca. 4.5 over a single injection. Nitrite, being the less concentrated metabolite in NO detection and thereby more difficult to detect, was calibrated with the HT-CE-UV method and a limit of detection (LOD) of 0.56 microM was obtained. Rat blood plasma was analyzed with this detection system and demonstrated to be comparable with NO metabolite concentrations of previously published results. This HT-CE-UV method is described where a unique reservoir tube design that contains 8-microL standard nitrite sample volumes is placed over the end of the capillary arm to explore low volume limits for biological samples.

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Correlation capillary zone electrophoresis, a novel technique to decrease detection limits

Cited by 33 publications

References 27 publications

Application of Hadamard transformation to MEKC

Application of Hadamard transformation to MEKC

Thermal marks as a signal processing aid for a portable capillary electropherograph

Hadamard transform CE-UV detection for biological samples

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