Parameters affecting reproducibility in capillary electrophoresis

Schaeper, James P.; Sepaniak, Michael J.

doi:10.1002/(sici)1522-2683(20000401)21:7<1421::aid-elps1421>3.0.co;2-7

Cited by 112 publications

(53 citation statements)

References 44 publications

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“…In order to increase the precision of the data, corrected migration times and corrected peak areas were used [22]. Corrected migration times were calculated as the migration time of the peak divided by the migration time corresponding to the electroosmotic flow (methanol).…”

Section: Data Treatmentmentioning

confidence: 85%

Enantiomeric separation of organophosphorus pesticides by capillary electrophoresis

García-Ruiz

Álvarez-Llamas

Puerta

et al. 2005

Analytica Chimica Acta

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The separation of the enantiomers of a group of organophosphorus pesticides (OPs) has been investigated by electrokinetic chromatography (EKC) using different anionic cyclodextrins as chiral selectors. The use of a 25 mM Tris buffer (pH 7.0), 20 mM in CM-␤-CD together with an applied voltage of 24 kV and a temperature of 25• C enabled the individual enantiomeric separation of malathion and phenthoate each one into its two enantiomers, the partial separation of the enantiomers of phenamiphos and the separation of three of the four enantiomers of isomalathion. Since naled is very reactive in aqueous solutions, its enantiomeric separation achieved in about 8 min in 25 mM borate buffer at pH 9 with 10 mM CM-␤-CD resulted in the observation of a broad peak due to degradation products. A preconcentration step by disk solid-phase extraction was studied and used together with the chiral EKC method developed for the enantiomeric separation of malathion in order to determine this pesticide in tap water samples spiked at the g mL −1 level. Finally, the precision and recovery of the method was established.

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Section: Data Treatmentmentioning

confidence: 85%

Enantiomeric separation of organophosphorus pesticides by capillary electrophoresis

García-Ruiz

Álvarez-Llamas

Puerta

et al. 2005

Analytica Chimica Acta

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“…Corrected peak areas (A c ) and corrected migration times (t c ) were used to compensate fluctuations in electrophoretic conditions and to obtain a good reproducibility of data [22]. A c was calculated dividing the peak area (A) by the corresponding migration time (t) and t c was calculated dividing the migration time (t) by the migration time of the EOF (t EOF ), i.e., A c = A/t and t c = t/t EOF .…”

Section: Data Treatmentmentioning

confidence: 99%

Development of a capillary electrophoresis method for the determination of soybean proteins in soybean–rice gluten‐free dietary products

2006

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Development of a capillary electrophoresis method for the determination of soybean proteins in soybean-rice gluten-free dietary products CE has been applied for the first time to the simultaneous separation of soybean and rice proteins. Treated and untreated capillaries with different effective lengths as well as separation media at different pHs were tested. For that purpose, samples and standard solutions were prepared in 25:75 ACN-water media containing 0.3% v/v acetic acid. The use of an untreated capillary of 50 cm effective length together with an 80 mM borate buffer (pH 8.5) modified with 20% v/v ACN and UV detection at 254 nm were the conditions working the best. These conditions enabled the determination of soybean proteins in gluten-free dietary commercial products elaborated with soybean protein and/or soybean flour and rice flour using the standard additions calibration method. The method was linear up to 26 mg/mL of soybean proteins, the precision (expressed as RSD) was always better than 6%, and recoveries obtained for soybean proteins when spiking commercial products were very close to 100%.

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“…Corrected peak areas (A c ) and corrected migration times (t c ) have been used to compensate fluctuations in electrophoretic conditions and to obtain a good reproducibility of data [24]. They have been calculated by dividing the peak area (A) by the corresponding migration time (t) and the migration times (t) by the migration time of the EOF (t EOF ), which was measured as the migration time corresponding to the solvent peak (methanol peak), that is, A c = A/t and t c = t/t EOF .…”

Section: Data Treatmentmentioning

confidence: 99%

Enantioselective separation of the sunscreen agent 3-(4-methylbenzylidene)-camphor by electrokinetic chromatography: Quantitative analysis in cosmetic formulations

2005

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Enantioselective separation of the sunscreen agent 3-(4-methylbenzylidene)-camphor by electrokinetic chromatography: Quantitative analysis in cosmetic formulations3-(4-Methylbenzylidene)-camphor (MBC) is a chiral sunscreen agent used in cosmetic products. In this work, the enantioseparation of MBC has been performed by EKC and applied to the analysis of the MBC enantiomers in cosmetic creams. Different experimental conditions (type and concentration of the chiral selector, temperature, and sample solvent) have been optimized. Due to the neutral nature of this compound, anionic CD derivatives were investigated as chiral selectors. Carboxymethylated-b-CD (CM-b-CD) showed the highest chiral separation power, observing that a 15 mM concentration of this CD at a working temperature of 157C enabled to obtain the highest enantioresolution. However, under these conditions, tailing of peaks obtained for the enantiomers was observed. The addition of increasing concentrations of the neutral a-CD to CM-b-CD at a 15 mM concentration in a 100 mM borate buffer at pH 9.0 improved the enantiomeric separation and decreased peak tailing. The use of DMF for the total dissolution of the cosmetic creams, and methanol:water (1:1 v/v) for appropriate dilution enabled to observe good shape and size for the peaks of the MBC enantiomers. After optimizing a method for the preconditioning of the capillary, the analytical characteristics of the chiral separation method for the analysis of MBC were investigated. Linearity, LODs and LOQs, precision (instrumental repeatability, method repeatability, intermediate precision), accuracy, and selectivity were evaluated.The method was applied to analyze MBC enantiomers contained in two commercial cosmetic creams containing racemic MBC and to study the skin absorption of this compound with time.

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Parameters affecting reproducibility in capillary electrophoresis

Cited by 112 publications

References 44 publications

Enantiomeric separation of organophosphorus pesticides by capillary electrophoresis

Enantiomeric separation of organophosphorus pesticides by capillary electrophoresis

Development of a capillary electrophoresis method for the determination of soybean proteins in soybean–rice gluten‐free dietary products

Enantioselective separation of the sunscreen agent 3-(4-methylbenzylidene)-camphor by electrokinetic chromatography: Quantitative analysis in cosmetic formulations

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