Determination of organic anions in atmospheric aerosol samples by capillary electrophoresis after reversed pre‐electrophoresis

Blanco-Heras, Gustavo; Turnes-Carou, Isabel; López-Mahı́a, Purificación; Muniategui-Lorenzo, Soledad; Prada‐Rodríguez, D.; Fernández-Fernández, Esther

doi:10.1002/elps.200700413

Cited by 17 publications

(14 citation statements)

References 30 publications

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“…The use of a single ISTD for improving precision in conventional CE with hydrodynamic injection has been well investigated and shown to improve intracolumn RSDs to less than 1% . Two ISTDs have also been verified to correct for run‐to‐run variation with EKI methods in conventional CE , as well the application of an ISTD to correct for overlapping peaks . While ISTDs have been employed in some MCE applications , minimal investigation has been done on the effect of ISTDs on chip‐to‐chip variability.…”

Section: Introductionmentioning

confidence: 99%

Improving chip‐to‐chip precision in disposable microchip capillary electrophoresis devices with internal standards

2015

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To realize portable systems for routine measurements in point-of-care settings, MCE methods are required to be robust across many single-use chips. While it is well-known internal standards (ISTDs) improve run-to-run precision, a systematic investigation is necessary to determine the significance of chip-to-chip imprecision in MCE and how ISTDs account for it. This paper addresses this question by exploring the reproducibility of Na quantification across six basic, in-house fabricated microchips. A dataset of 900 electrophoerograms was collected from analyzing five concentrations of NaCl with two ISTDs (CsCl and LiCl). While both improved the peak area reproducibility, the Na/Cs ratio was superior to the Na/Li ratio (improving the RSD by a factor of 2-4, depending on the Na concentration). We attribute this to the significant variation in microchannel surface properties, which was accounted for by cesium but not lithium. Microchip dimension and detector variations were only a few percent, and could be improved through commercial fabrication over in-house made microchips. These results demonstrate that ISTDs not only correct for intrachip imprecision, but are also a viable means to correct for chip-to-chip imprecision inherent in disposable, point-of-care MCE devices. However, as expected, the internal standard must be carefully chosen.

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Section: Introductionmentioning

confidence: 99%

Improving chip‐to‐chip precision in disposable microchip capillary electrophoresis devices with internal standards

2015

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“…1−4 Adding an internal standard (ISTD) to the sample is a standard technique used to improve run-to-run quantification in conventional capillary electrophoresis (CE) 5−7 and MCE. 8,9 In a recent paper, we demonstrated that adding an ISTD to the sample can be used not only to improve run-to-run quantification, but also improve chip-to-chip precision.…”

mentioning

confidence: 99%

Integrating Internal Standards into Disposable Capillary Electrophoresis Devices To Improve Quantification

Bidulock¹,

Dubský

Berg³

et al. 2017

Anal. Chem.

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To improve point-of-care quantification using microchip capillary electrophoresis (MCE), the chip-to-chip variabilities inherent in disposable, single-use devices must be addressed. This work proposes to integrate an internal standard (ISTD) into the microchip by adding it to the background electrolyte (BGE) instead of the sample—thus eliminating the need for additional sample manipulation, microchip redesigns, and/or system expansions required for traditional ISTD usage. Cs and Li ions were added as integrated ISTDs to the BGE, and their effects on the reproducibility of Na quantification were explored. Results were then compared to the conclusions of our previous publication which used Cs and Li as traditional ISTDs. The in-house fabricated microchips, electrophoretic protocols, and solution matrixes were kept constant, allowing the proposed method to be reliably compared to the traditional method. Using the integrated ISTDs, both Cs and Li improved the Na peak area reproducibility approximately 2-fold, to final RSD values of 2.2–4.7% (n = 900). In contrast (to previous work), Cs as a traditional ISTD resulted in final RSDs of 2.5–8.8%, while the traditional Li ISTD performed poorly with RSDs of 6.3–14.2%. These findings suggest integrated ISTDs are a viable method to improve the precision of disposable MCE devices—giving matched or superior results to the traditional method in this study while neither increasing system cost nor complexity.

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“…To reduce residual error, it is common practice in CE and microchip CE to add an internal standard (ISTD) to the sample. In a recent paper, we verified the significance of chip‐to‐chip differences in quantification imprecision with a systematic investigation across six microfluidic chips, and further determined how well two ISTDs (Cs and Li) accounted for this error .…”

Section: Introductionmentioning

confidence: 99%

Integrated internal standards: A sample prep‐free method for better precision in microchip CE

et al. 2018

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Point‐of‐care systems based on microchip capillary electrophoresis require single‐use, disposable microchips prefilled with all necessary solutions so an untrained operator only needs to apply the sample and perform the analysis. While microchip fabrication can be (and has been) standardized, some manufacturing differences between microchips are unavoidable. To improve analyte precision without increasing device costs or introducing additional error sources, we recently proposed the use of integrated internal standards (ISTDs): ions added to the BGE in small concentrations which form system peaks in the electropherogram that can be used as a measurement reference. Here, we further expand this initial proof‐of‐principle test to study a clinically‐relevant application of K ion concentrations in human blood; however, using a mock blood solution instead of real samples to avoid interference from other obstacles (e.g. cell lysis). Cs as an integrated ISTD improves repeatability of K ion migration times from 6.97% to 0.89% and the linear calibration correlation coefficient (R2) for K quantification from 0.851 to 0.967. Peak area repeatability improves from 11.6–13.3% to 4.75–5.04% at each K concentration above the LOQ. These results further validate the feasibility of using integrated ISTDs to improve imprecision in disposable microchip CE devices by demonstrating their application for physiological samples.

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Determination of organic anions in atmospheric aerosol samples by capillary electrophoresis after reversed pre‐electrophoresis

Cited by 17 publications

References 30 publications

Improving chip‐to‐chip precision in disposable microchip capillary electrophoresis devices with internal standards

Improving chip‐to‐chip precision in disposable microchip capillary electrophoresis devices with internal standards

Integrating Internal Standards into Disposable Capillary Electrophoresis Devices To Improve Quantification

Integrated internal standards: A sample prep‐free method for better precision in microchip CE

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