Characteristics of new composite- and classical potentiometric sensors for the determination of pharmaceutical drugs

Vissers, Bert; Bohets, Hugo; Everaert, Joseph; Cool, Pegie; Vansant, Etienne F.; Prez, Filip Du; Kauffmann, J.M.; Nagels, L.J.

doi:10.1016/j.electacta.2006.03.040

Cited by 22 publications

(14 citation statements)

References 23 publications

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“…3, but at the higher concentrations (c analyte above 2 10 -4 M injected or log c analyte = -3.66), the responses (mV) were suppressed. Therefore, we did not give S values for the dT 20 and dT 30 curves. It is however clear from Fig.…”

Section: Potentiometric Calibration Curves For Oligonucleotidesmentioning

confidence: 83%

“…Responses of ionic molecules towards potentiometric sensors can be linked to their Gibbs free energy difference between the eluent phase and the membrane coating phase [19]. For small organic molecules such as pharmaceutical drugs, logP values are a good indicator to predict these responses [20]. The behaviour of highly charged anions in this respect is still open to investigation.…”

Section: Molar Responses and Detection Limitsmentioning

confidence: 99%

“…Oligonucleotides dT 10 , dT 20 and dT 30 were injected in equimolar amounts in an HPLC setup equipped with a UV detector (260 nm) and a potentiometric detector. The UV detector was used as a detector reflecting the true concentration profile giving negligible peak broadening.…”

Section: Potentiometric Calibration Curves For Oligonucleotidesmentioning

confidence: 99%

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Response of DNA Fragments to Potentiometric Sensors Studied Using HPLC

Nagels¹,

Everaert²,

Bohets³

et al. 2007

CCHTS

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Potentiometric sensors are studied as viable candidates for the construction of high throughput DNA arrays. For preliminary investigations, such sensors were used in an HPLC setup in the present work. This avoided errors due to ionic contaminants or additives in the commercial samples. The oligonucleotides dT(10), dT(20) and dT(30) were used as test substances. The potentiometric sensors were of the coated wire type, containing PVC, DOP, MTDDACl and a synthetic podand urea receptor. The HPLC system consisted of a reversed phase column eluted with a phosphate buffer, triethylammoniumacetate (TEAA), and an acetonitrile gradient. Molar responses and sensitivities increased with increasing chain length of oligonucleotides, yielding detection limits as low as 10(-6)M (dT(30), injected concentration). The slopes of the calibration graphs were at least 23 mV/decade (dT(10)), which was much higher than expected. The results are discussed in view of the potential use of this sensor type in high throughput microarrays.

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Section: Potentiometric Calibration Curves For Oligonucleotidesmentioning

confidence: 83%

Section: Molar Responses and Detection Limitsmentioning

confidence: 99%

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Response of DNA Fragments to Potentiometric Sensors Studied Using HPLC

Nagels¹,

Everaert²,

Bohets³

et al. 2007

CCHTS

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“…The electrodes were allowed to dry for at least 2 h. Afterwards they were kept in deionized water overnight or in the appropriate HPLC eluent in the case of the MPI_Comp-electrode. Prior to use, the electrodes were conditioned with the running eluent in the HPLC system (l30 min) until a stable baseline was observed [22]. The compositesubstrate (Comp)-based electrodes showed a much higher durability in the HPLC conditions with high (>30%) ACN concentrations in the mobile phase because of the better mechanical attachment of the ion-selective membrane to the surface of substrate in comparison to the glassy carbon-substrate (CW)-based electrodes.…”

Section: Composition Of Different Electrode Coating Typesmentioning

confidence: 99%

Unique potentiometric detection systems for HPLC determination of some steroids in human urine

Vissers¹,

Everaert²,

Sekuła³

et al. 2009

J of Separation Science

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Unique potentiometric detection systems for HPLC determination of some steroids in human urineIsocratic HPLC with potentiometric detection is used for the determination of some 17-ketosteroids (17-KS), e.g., androsterone, dehydroepiandrosterone and estrone, and their respective sulfated conjugates (17-KSS). Glassy carbon or composite electrodes containing a mixture of graphite and poly(vinyl chloride), PVC, were used as substrate electrodes. These substrates were covered either by montmorillonite or potassium tetrakis(p-chlorophenyl) borate containing PVC-based rubber phase membranes. The neutral 17-KS compounds were derivatized with Girard's reagent P (GP) to obtain cationic pyridinium acetohydrazones prior to the HPLC/potentiometric detection assay. No side reactions were observed, and the GP itself was not interfering. The method yielded accurate and reproducible results and was applicable to samples containing down to micromolar concentrations. Next, the 17-KSS compounds, acting as anionic charged molecules, were determined directly in human urine samples with the HPLC/potentiometry combination without preliminary derivatization. For this purpose, a new anion-sensitive potentiometric electrode was developed using a macrocyclic polyamine containing, PVC-based, rubber phase membrane. The three 17-KSS compounds were also determined accurately down to micromolar concentrations. Especially, the main androgen metabolites as dehydroepiandrosterone sulfate and androsterone sulfate could be selectively determined with a developed potentiometric sensor in human urine samples without time-consuming cleanup and preconcentration step. IntroductionThe 17-ketosteroids (17-KS) are steroids with a ketone functional group at position 17 in their polycyclic carbon skeleton. Typical examples are dehydroepiandrosterone (DHEA), estrone (E 1 ), and androsterone (AD), see Scheme (1) for their structures. DHEA, a representative 17-KS, is synthesized by the adrenal gland and then converted into active hormones, estrogens, and androgens, in the peripheral tissues. Most of the DHEA (over 99%) is present in the blood as the sulfated conjugate (dehydroepiandrosterone sulfate (DHEAS)), which is second to cholesterol in abundance for circulating steroids in humans. In both sexes, serum DHEA levels vary profoundly throughout life. Levels start to increase in children, peakCorrespondence: Professor Grzegorz Bazylak, Department of Pharmaco-Bromatology & Molecular Nutrition, Faculty of Pharmacy, Collegium Medicum, Nicolaus Copernicus University, Jagiellonska 13, PL-85-067 Bydgoszcz, Poland E-mail: gbazylak@cm.umk.pl Fax: +4852-585-3817Abbreviations: AD, androsterone; AD-GP, androsterone derivatized with Girard's reagent P; ADS, androsterone sulfate; BOR_-Comp, TCPB containing graphite/PVC composite electrode used in repeated over several days measurements of sequence of different injected concentration of the analyte; BOR_Comp_1-day, TCPB containing graphite/PVC composite electrode used in consequtive measurements of the same injected concent...

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“…E-mail: mashhadizadeh@tmu.ac.ir selective electrode [8]. Sample preparation techniques prior to instrumental analysis were based on liquid-liquid extraction (LLE) [9] and solid phase extraction (SPE) [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Cloud point extraction and spectrophotometric determination of codeine in pharmaceutical and biological samples

Mashhadizadeh¹,

Jafari²

2010

JICS

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Cloud point extraction process using non-ionic surfactant, Triton X-114, to extract codeine from aqueous solution was investigated. The method was based on the extraction of codeine and bromothymol blue from acetate buffer media to surfactantrich phase and formed a charge transfer-ion pair complex. The extracted surfactant-rich phase was diluted with ethanol and its absorbance was measured at 430 nm. The effect of different variables such as pH, Triton X-114 concentration, cloud point temperature and time was established. The calibration graph was linear in a wide range of 100 -700 ng ml -1 of codeine with r = 0.998 (n = 7). The detection limit based on three times standard deviation of the blank (3s) was 4.6 ng ml -1 and relative standard deviation (R.S.D) is 2.15% for 500 ng ml -1 codeine (n = 5). The proposed method was applied to the determination of codeine in acetaminophen codeine tablets and blood samples.

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Characteristics of new composite- and classical potentiometric sensors for the determination of pharmaceutical drugs

Cited by 22 publications

References 23 publications

Response of DNA Fragments to Potentiometric Sensors Studied Using HPLC

Response of DNA Fragments to Potentiometric Sensors Studied Using HPLC

Unique potentiometric detection systems for HPLC determination of some steroids in human urine

Cloud point extraction and spectrophotometric determination of codeine in pharmaceutical and biological samples

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