On the formation of carbonate adducts of fatty alcohols, sterols, and sugars in biological conditions

Lago, Claudimir Lúcio do; Vidal, Denis Tadeu Rajh; Rossi, Marcelo Rabello; Hotta, Guilherme Minoru; Costa, Eric Tavares da

doi:10.1002/elps.201200080

Cited by 14 publications

(26 citation statements)

References 32 publications

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“…It is also important to mention that the large surface‐to‐volume ratio in the device is significantly higher than the ratios obtained in a standard bench‐top titration. Therefore, to completely eliminate the interference of CO 2 , additional elements or steps should be included, such as to enclose the system in an inert atmosphere or degas the solutions with N 2 .…”

Section: Resultsmentioning

confidence: 99%

Getting started with open‐hardware: Development and control of microfluidic devices

et al. 2014

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Understanding basic concepts of electronics and computer programming allows researchers to get the most out of the equipment found in their laboratories. Although a number of platforms have been specifically designed for the general public and are supported by a vast array of on-line tutorials, this subject is not normally included in university chemistry curricula. Aiming to provide the basic concepts of hardware and software, this article is focused on the design and use of a simple module to control a series of PDMS-based valves. The module is based on a low-cost microprocessor (Teensy) and open-source software (Arduino). The microvalves were fabricated using thin sheets of PDMS and patterned using CO2 laser engraving, providing a simple and efficient way to fabricate devices without the traditional photolithographic process or facilities. Synchronization of valve control enabled the development of two simple devices to perform injection (1.6 ± 0.4 μL/stroke) and mixing of different solutions. Furthermore, a practical demonstration of the utility of this system for microscale chemical sample handling and analysis was achieved performing an on-chip acid-base titration, followed by conductivity detection with an open-source low-cost detection system. Overall, the system provided a very reproducible (98%) platform to perform fluid delivery at the microfluidic scale.

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Section: Resultsmentioning

confidence: 99%

Getting started with open‐hardware: Development and control of microfluidic devices

et al. 2014

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“…This pH ensures that the POCs are in their anionic form, and the low mobility of CHES leads to positive peaks for these species . One can note that there is a reduction of the relative area of the performate peak from the first to the second detector, which is used in the calculation of the kinetic constant of hydrolysis .…”

Section: Resultsmentioning

confidence: 99%

“…Three POCAs were adopted for this purpose: performic, peracetic, and perpropionic acids. The approach is similar to that one recently introduced for studies about monoalkyl carbonates (MAC): another class of low‐stability species . In brief, peaks for the percarboxylate ions are recorded at two detectors positioned along the capillary.…”

Section: Introductionmentioning

confidence: 99%

Capillary electrophoresis with capacitively coupled contactless conductivity detection applied to the quantitation and to the determination of physical–chemical properties of peroxycarboxylates in aqueous medium

Vidal

Lago

2013

Electrophoresis

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CE with C⁴D (CE-C⁴D) was successfully applied to the investigation of performate, peracetate, and perpropionate in aqueous medium. Ionic mobilities, diffusion coefficients, and hydrodynamic radii were obtained for the first time for these species. CE-C⁴D was also used to estimate the pKa values of the peroxycarboxylic acids. Because the peroxycarboxylates (POCs) undergoes hydrolysis while migrating, a simple calibration curve cannot be used for quantitation. Thus, an indirect calibration approach was used. The new method was used to monitor the formation of peroxycarboxylic acids from hydrogen peroxide and the carboxylic acid as well as to the quantitation of peracetic acid in a commercial sample. The CE-C⁴D method compares favorably with the conventional titration method because of the possibility of speciation of the POC, the low sample consumption, and the low LOD (14, 8, and 24 μmol/L for performate, peracetate, and perpropionate, respectively). Although POCs are structural isomers of monoalkyl carbonates, they have greater hydrodynamic radii, which suggests that the positions of the oxygen atoms in the molecules have a direct impact in the charge density and consequently on the hydration atmosphere.

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“…This approximation allows the calibration of a conductivity detector by using a surrogate for the analyte. Actually, this approach has been successfully used to calibrate C 4 D for unstable species . Other opportunities for such an indirect calibration are the unavailability of standards of rare, new, expensive, dangerous, or illegal substances.…”

Section: Discussionmentioning

confidence: 99%

A capillary electrophoresis system with dual capacitively coupled contactless conductivity detection and electrospray ionization tandem mass spectrometry

Francisco

Lago

2016

Electrophoresis

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A commercial system that is comprised of a CE coupled to an ESI triple quadrupole mass spectrometer was equipped with two capacitively coupled contactless conductivity detectors (C(4) Ds). The first C(4) D was positioned inside the original cartridge, and the second C(4) D was positioned as close as possible to the ESI probe entrance by using a 3D-printed support. The C(4) Ds electropherograms were matched to the ESI-MS electropherogram by correcting their timescales by the factor LT /LD , where LT and LD are the total capillary length and the length until the C(4) D, respectively. A general approach for method development supporting the simultaneous conductivity and MS detection is discussed, while application examples are introduced. These examples include the use of C(4) D as a simple device that dismiss the use of an EOF marker, a low-selectivity detector that continuously provide information about unexpected features of the sample, and even a detector that can be more sensitive than ESI-MS. The C(4) D used in this setup proved to have a smaller contribution to the peak broadening than ESI-MS, which allowed that a C(4) D, positioned at 12 cm from the inlet of an 80-cm-long capillary, could be used to foresee position and shape of the peaks being formed 6.8 times slower at the ESI-MS electropherogram.

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On the formation of carbonate adducts of fatty alcohols, sterols, and sugars in biological conditions

Cited by 14 publications

References 32 publications

Getting started with open‐hardware: Development and control of microfluidic devices

Getting started with open‐hardware: Development and control of microfluidic devices

Capillary electrophoresis with capacitively coupled contactless conductivity detection applied to the quantitation and to the determination of physical–chemical properties of peroxycarboxylates in aqueous medium

A capillary electrophoresis system with dual capacitively coupled contactless conductivity detection and electrospray ionization tandem mass spectrometry

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