Biomedical subjects

G Palleschi

Publications and source records attributed to G Palleschi.

At least 19 recordsLinked to original sources

PubMed2007

NADH screen-printed electrodes modified with zirconium phosphate, Meldola blue, and Reinecke salt. Application to the detection of glycerol by FIA.

Bulk screen-printed electrodes (bSPEs) modified with zirconium phosphate (ZrP) and Meldola blue (MB) and by electrochemical deposition of a Reineckate film (bMBZrPRs-SPEs) have been constructed and used as NADH sensors. Cyclic voltammetric investigation of these bulk electrochemically modified screen-printed electrodes revealed stable catalytic activity in oxidation of the reduced form of the coenzyme nicotinamide adenine dinucleotide (NADH). Flow-injection analysis (FIA) coupled with amperometric detection confirmed the improved stability of the bMBZrPRs-SPEs (10(-4) mol L(-1) NADH, %RSD = 4.2, n = 90, pH 7.0). Other conditions, for example applied working potential (+50 mV relative to Ag|AgCl), flow rate (0.30 mL min(-1)) and pH-dependence (range 4.0-10.0) were evaluated and optimized. A glycerol biosensor, prepared by immobilizing glycerol dehydrogenase (GDH) on the working electrode area of a bMBZrPRs-SPE, was also assembled. The biosensor was most stable at pH 8.5 (%RSD = 5.6, n = 70, 0.25 mmol L(-1) glycerol). The detection and quantification limits were 2.8 x 10(-6) and 9.4 x 10(-6) mol L(-1), respectively, and the linear working range was between 1.0 x 10(-5) and 1.0 x 10(-4) mol L(-1). To assess the effect of interferences, and recovery by the probe we analyzed samples taken during fermentation of chemically defined grape juice medium and compared the results with those obtained by HPLC.

Beverages↗

PubMed2006

Electrochemical immunosensor array using a 96-well screen-printed microplate for aflatoxin B1 detection.

A novel analytical immunosensor array, based on a microtiter plate coupled to a multichannel electrochemical detection (MED) system using the intermittent pulse amperometry (IPA) technique, is proposed for the detection of aflatoxin B1 (AFB1). In the present work, the electrochemical behaviour and electroanalytical performance of the thick-film carbon sensors (also designated as screen-printed electrodes) incorporated in the multichannel electrochemical plate were first evaluated. Then the 96-well screen-printed microplate was modified in accord with a competitive indirect enzyme-linked immunoassay (ELISA) format for aflatoxin B1 detection. The measurements were performed using both spectrophotometric and electrochemical procedures and the results of the calibration curves, detection limit (LOD), sensitivity and reproducibility of the respective assay systems were evaluated. The immunoassay was then applied for analysis of corn samples spiked with AFB1 before and after the extraction treatment, in order to study the extraction efficiency and the matrix effect, respectively. These studies have shown that using this system, AFB1 can be measured at a level of 30 pg/mL and with a working range between 0.05 and 2 ng/mL. Good recoveries (103+/-8%) were obtained, demonstrating the suitability of the proposed assay for accurate determination of the AFB1 concentration in corn samples. The specificity of the assay was assessed by studying the cross-reactivity of PAb relative to AFB1. The results indicated that the PAb could readily distinguish AFB1 from other aflatoxins, with the exception for AFG1.

Aflatoxin B1↗

PubMed2006

Study of a toxin-alkaline phosphatase conjugate for the development of an immunosensor for tetrodotoxin determination.

This paper describes a direct competitive immunoenzymatic spectrophotometric assay (ELISA) for tetrodotoxin (TTX) determination and the adaptation of this method for use in an electrochemical assay format. The novelty of this work involves the use of the antigen labelled with alkaline phosphatase (AP); this conjugate was prepared in our laboratory as there is no commercially available conjugate of any kind for TTX. The new conjugate was characterized in terms of its affinity for the specific antibody as well as the residual concentration and the residual activity of the enzyme (AP) incorporated as label. The proposed method based on the new conjugate showed satisfactory results for TTX determination: for the spectrophotometric method the dynamic range was 4-15 ng mL(-1) with a limit of detection (LOD) of 2 ng mL(-1) (R=0.9247), whereas for the electrochemical protocol the dynamic range was 2-50 ng mL(-1) and the LOD was 1 ng mL(-1).

Alkaline Phosphatase↗

PubMed2006

Early echographical assessment of minimal lesions of cavernosum corpora and tunica albuginea in subjects with erectile dysfunction, suggestive of La Peyronie's disease.

The aim of the study is to evaluate the incidence and the echographic characteristics of minimal lesions of cavernosum corpora and tunica albuginea (TA) in subjects reporting erectile dysfunction (ED), which could suggest the suspicious of La Peyronie's disease (LPD). In total, 185 patients (pts) underwent dynamic penile Ultrasound Color Doppler (USCD) for ED. None of the pts presented any clinical symptoms or any clinical findings for LPD. In this study we evaluated, using USCD, thickness, echogenicity, regularity of the surface profile of the dorsal TA, the intercavernous and the intercaverno-spongeous septa, and the extension of the eventual pathologic lesions. In all, 16 pts (8.7%) presented minimal lesions at the ultrasound examinations. In nine of these pts (56%) the lesion was localized at the dorsal position, in six (38%) on the intercavernous septum and in one patient (6%) in both positions. The dorsal lesions were represented in nodular form in four pts (4%), and in diffuse form in five pts (55%). The nodular form was present in all the intercavernous septal lesions observed. As reported in the literature, USCD represents the investigative technique of choice in the study of LPD and in ED. Furthermore, the results of this study suggest that this technique could allow the localization of minimal lesions attributable to LPD during a preclinical phase of this disease. The localization of these lesions could permit to start a therapeutic approach during an early phase of the disease.

Adolescent↗

PubMed2005

Acetylcholinesterase sensor based on screen-printed carbon electrode modified with prussian blue.

Acetylcholinesterase (ChE) sensor based on Prussian blue (PB) modified electrode was developed and tested for the detection of organophosphorus and carbamic pesticides. The signal of the sensor was generated in PB mediated oxidation of thiocholine recorded at +200 mv in DC mode. ChE from electric eel was immobilized by cross-linking with glutaraldehyde in the presence of bovine serum albumin (BSA) on the surface of screen-printed carbon electrode covered with PB and Nafion. The content of the surface layer (specific enzyme activity, Nafion and BSA amounts) was optimized to establish high and reliable response toward the substrate and ChE inhibitors. The ChE/PB sensor makes it possible to detect Aldicarb, Paraoxon and Parathion-Methyl with limits of detection 30, 10 and 5 ppb, respectively (incubation 10 min). The feasibility of practical application of the ChE/PB sensor developed for the monitoring of degradation of the pesticides in wine fermentation was shown. To diminish matrix interferences, the electrolysis of the grape juice with Al anode and evaporation of ethanol were suggested, however the procedures decrease the sensitivity of pesticide detection and stability of the sample tested.

Acetylcholinesterase↗

PubMed2005

An electrochemical immunosensor for aflatoxin M1 determination in milk using screen-printed electrodes.

The production and assembling of disposable electrochemical AFM1 immunosensors, which can combine the high selectivity of immunoanalysis with the ease of the electrochemical probes, has been carried out. Firstly immunoassay parameters such as amounts of antibody and labelled antigen, buffer and pH, length of time and temperature of each steps (precoating, coating, binding and competition steps) were evaluated and optimised in order to set up a spectrophotometric enzyme-linked immunosorbent assay (ELISA) procedure. This assay exhibited a working range between 30 and 160 ppt in a direct competitive format. Then electrochemical immunosensors were fabricated by immobilising the antibodies directly on the surface of screen-printed electrodes (SPEs), and allowing the competition to occur between free AFM1 and that conjugated with peroxidase (HRP) enzyme. The electrochemical technique chosen was the chronoamperometry, performed at -100 mV. Furthermore, studies of interference and matrix effects have been performed to evaluate the suitability of the developed immunosensors for the analysis of aflatoxin M1 directly in milk. Results have shown that using screen-printed electrodes aflatoxin M1 can be measured with a detection limit of 25 ppt and with a working range between 30 and 160 ppt. A comparison between the spectrophotometric and electrochemical procedure showed that a better detection limit and shorter analysis time could be achieved using electrochemical detection.

Aflatoxin M1↗

PubMed2005

Novel planar glucose biosensors for continuous monitoring use.

Novel planar glucose biosensors to be used for continuous monitoring have been developed. The electrodes are produced with the "screen printing" technique, and present a high degree of reproducibility together with a low cost and the possibility of mass production. Prior to enzyme immobilisation, electrodes are chemically modified with ferric hexacyanoferrate (Prussian Blue). This allows the detection of the hydrogen peroxide produced by the enzymatic reaction catalysed by GOD, at low applied potential (ca. 0.0 V versus Ag/AgCl), highly limiting any electrochemical interferences. The layer of Prussian Blue (PB) showed a high stability at the working conditions (pH 7.4) and also after 1 year of storage dry at RT, no loss of activity was observed. The assembled glucose biosensors, showed high sensitivity towards glucose together with a long-term operational and storage stability. In a continuous flow system, with all the analytical parameters optimised, the glucose biosensors detected glucose concentration as low as 0.025 mM with a linear range up to 1.0mM. These probes were also tested over 50-60 h in a continuous flow mode to evaluate their operational stability. A 0.5 mM concentration of glucose was continuously fluxed into a biosensor wall-jet cell and the current due to the hydrogen peroxide reduction was continuously monitored. After 50-60 h, the drift of the signal observed was around 30%. Because of their high stability, these sensors suggest the possibility of using such biosensors, in conjunction with a microdialysis probe, for a continuous monitoring of glucose for clinical purposes.

Biosensing Techniques↗

PubMed2005

Sensor and biosensor preparation, optimisation and applications of Prussian Blue modified electrodes.

Being one of the most commonly used electrochemical mediators for analytical applications, Prussian Blue has found a wide use in the biosensor field during the last years. Its particular characteristic of catalysing hydrogen peroxide reduction has been applied in the construction of a large number of oxidase enzyme-based biosensors for clinical, environmental and food analysis. By modifying an electrode surface with Prussian Blue, it is in fact possible to easily detect hydrogen peroxide at an applied potential around 0.0 V versus Ag/AgCl, thus making possible coupling with oxidase enzymes while also avoiding or reducing electrochemical interferences. Papers dealing with glucose, lactate, cholesterol and galactose biosensors that are based on the use of Prussian Blue have recently appeared in the most important analytical chemistry journals. Another recent trend is the use of a choline probe based on choline oxidase for pesticide determination to exploit the inhibition of acetylcholinesterase by these compounds. In addition, the use of Prussian Blue in the development of biosensors for food analysis has captured the interest of many research groups and led to improved methods for the detection of glutamate, galactose, alcohol, fructosyl amine, formate, lysine and oxalate. This review will focus on the biosensing aspects of Prussian Blue-based sensors giving a general overview of the advantages provided by such mediator as well as its drawbacks. A comprehensive bibliographic reference list is presented together with the most up to date research findings in this field and possible future applications. The commercial potential of sensors based on this mediator will also be discussed.

Biosensing Techniques↗

PubMed2005

[Overactive bladder: modulating the effects of antimuscarinic therapy].

Overactive bladder (OAB) is a prevalent pathologic condition affecting millions of young, adult and aging people in the world. Although it is a underestimated disease, it causes a significant negative socio-economic impact and determines a severe deterioration of quality of life (QoL) of sufferers. The epidemiologic data today available regarding OAB incidence, prevalence and burden, have prompted a great interest about it. The effect of this research resulted in the availability of new clinical tools useful to investigate and easier diagnose OAB, such as voiding diary and specific symptomatic questionnaires. The most used drugs in the OAB treatment are the antimuscarinics, whose use is still limited due to their some side effects, mostly dry mouth and constipation. For this reason the pharmacologic research is involved in the development of drugs with a better receptorial selectivity, organ specificity, new extended release formulations or new ways of administration. The new extended release formulation of tolterodine, one of the most used drugs in OAB treatment, present a better tolerability maintaining its efficacy, with a consequent better therapeutic efficacy. Furthermore, the recent proposed night-time administration of the drug resulted in a even more lowering of side-effects due to their occurrence during the nocturnal resting.

Humans↗

PubMed2004

Pt based enzyme electrode probes assembled with Prussian Blue and conducting polymer nanostructures.

Conductive polymer nanotubules of 1,2-diaminobenzene (1,2-DAB) were prepared using a porous polycarbonate membrane template, placed on a Pt foil and used to support the polymer, then, the electropolymerisation was performed by chronocoulometry. The obtained conductive polymer nanostructures were then placed on Pt electrode and used to support highly dispersed prussian blue (PB), which acts as the active component for H2O2 detection. The observed good stability of PB as catalyst of H2O2 was related to the presence of organic non-conventional conducting polymers in a composite nanostructured film. These nanostructured polymer/PB composite films were also characterised by scanning electron microscopy (SEM) and Raman spectroscopy. The non-conventional conducting polymer nanotubules/PB modified Pt electrodes were tested by cyclic voltammeter for stability at different pH values, then, by amperometry, for hydrogen peroxide, ascorbic acid, acetaminophen, uric acid and acetylcholine. Glucose oxidase (GOD), lactate oxidase (LOD), L-amino acid oxidase (L-AAOD), alcohol oxidase (AOD), glycerol-3-phosphate oxidase (GPO), lysine oxidase (LyOx), and choline oxidase (ChOx) were immobilised on PB layer supported on 1,2-diaminobenzene (1,2-DAB) nanotubules onto the Pt electrodes. Different strategies for enzyme immobilisation were performed and used. Analytical parameters such as reproducibility, interference rejection, response time, storage and operational stability of the sensors have been studied and optimised. Results provide a guide to design high sensitive, stable and interference-free biosensors. The glucose biosensors assembled with nanostructured poly(1,2-DAB) showed a detection limit of 5 x 10(-5) mol l(-1), a wide linearity range (5 x 10(-5) to 5 x 10(-3) mol l(-1)), a high selectivity, a stability of 3 months at 4 degrees C, and at least 4 weeks at room temperature. Similar analytical parameters and stability were also studied for L-(+)-lactic acid, L-leucine, ethanol, glycerol-3-phosphate, lysine, and choline biosensors.

Biosensing Techniques↗

PubMed2004

Disposable immunosensor for the determination of domoic acid in shellfish.

The construction of an electrochemical immunosensor coupled to differential pulse voltammetry (DPV) for the detection of domoic acid (DA), a neurotoxic aminoacid responsible for the human syndrome known as "Amnesic Shellfish Poisoning" (ASP), is proposed here. The method involves the use of disposable screen-printed electrodes (SPEs) for the immunosensor development based on a "competitive indirect test". Domoic acid conjugated to bovine serum albumin (BSA-DA) was coated onto the working electrode of the SPE, followed by incubation with sample (or standard toxin) and anti-DA antibody. An anti-goat IgG-alkaline phosphatase (AP) conjugate was used for signal generation. A spectrophotometric enzyme-linked immunosorbent assay (ELISA) was used in a preliminary phase of development, prior to transferring the assay to the SPEs. Results showed a detection limit equal to 5 ng/ml of toxin. The electrochemical system is simple and cost-effective due to the disposable nature of the SPEs, and the analysis time is 150 min, shorter than that for the spectrophotometric method. The suitability of the assay for DA quantification in mussels was also evaluated. Samples were spiked with DA before and after the sample treatment to study the extraction efficiency and the matrix effect, respectively. After treatment, samples were analysed using a 1:250 v/v dilution in PBS-M (phosphate saline buffer pH 7.4 + CH3OH 10%) to minimise the matrix effect and allow for the detection of 20 microg/g of DA in mussel tissue. This represents the maximum acceptable limit defined by the Food and Drug Administration [Compliance Programme 7303.842. Guidance Levels, Table 3, p. 248, http://www.fda.org]. The optimised ELISA systems were then used, in parallel with a conventional HPLC method, to detect and confirm DA in shellfish extract in order to verify the performance of the electrochemical system. Very good recoveries were obtained, demonstrating the suitability of the proposed assay for accurate determination of the DA concentration in mussel samples.

Alkaline Phosphatase↗

PubMed2004

Chemical reversibility and stable low-potential NADH detection with nonconventional conducting polymer nanotubule modified glassy carbon electrodes.

Studies of the oxidation of beta-nicotinamide adenine dinucleotide (NADH) at glassy carbon (GCEs) electrode surfaces, modified with nonconventional conducting polymer nanotubules, are reported. In contrast to the situation with conventional carbon electrodes, chemical reversibility of the NADH oxidation reaction was achieved by means of poly(1,2-diaminobenzene) conducting nanotubule coatings. A Delta E(p) of 425 mV (vs Ag/AgCl; pH 7.0) was observed. The NADH amperometric response of the conducting nanotubule modified GCEs was shown to be extremely stable, with 98% of the initial response remaining after 48 h of stirring in the presence of 1 x 10(-4) M NADH solutions (compared to 14% at the poly(1,2-diaminobenzene) modified GCEs). The nonconventional conducting polymer nanotubule-coated electrodes, when tested in amperometric mode for NADH electrochemical oxidation at an applied potential of 450 mV, showed a sensitivity of 99 nA/mM, an operational stability for 2 days, a storage stability of 2 weeks at 4 degrees C, a linearity from 5 x 10(-5) to 1 x 10(-3) M, and good NADH chemical reversibility, all of which make them useful tools for dehydrogenase enzyme probe assembly.

Biosensing Techniques↗

PubMed2004

Experience with a bone anchor sling for treating female stress urinary incontinence: outcome at 30 months.

OBJECTIVES: To evaluate the clinical and video-urodynamic outcome in women with by stress urinary incontinence (SUI) treated with a bone-anchored pubovaginal sling. PATIENTS AND METHODS: The study included 70 women with SUI (as evaluated by a clinical examination, a voiding questionnaire, a short pad-test and video-urodynamics) who had a bone-anchor sling procedure, with or without cystocele repair, from January 1999 to December 2001; they were re-evaluated after a long-term follow-up (mean 30 months). RESULTS: The long-term outcome showed a success rate of > 95%; the clinical and video-urodynamic findings showed good functional and anatomical results, and an improvement in voiding performance in most patients. There was a low incidence of complications during and after surgery (2.8%). CONCLUSIONS: This approach gives, in highly selected patients, a high success rate and low incidence of complications. The technique is easy to learn and the costs to the financing bodies and public healthcare are low, making it a candidate for an alternative procedure to the standard techniques for SUI.

Female↗

PubMed2003

Analysis of erythromycin and tylosin in bovine muscle using disposable screen printed electrodes.

A disposable electrochemical enzyme-linked immunosorbent assay (ELISA) for the detection of two macrolides (erythromycin and tylosin) in bovine muscle was developed using a screen printed electrode (SPE) system as a differential pulse voltammetry (DPV) transducer with mouse anti-erythromycin (and anti-tylosin) monoclonal antibodies (MAb) serving as molecular recognition elements. The immunochemical system makes use of the competition assay principle, and employs an erythromycin (or tylosin)-BSA conjugate as coating molecule. After competition between free and coated analyte for the antibodies, the activity of the alkaline phosphatase labelled antiglobulins was measured electrochemically using 1-naphthylphosphate as substrate. Using standard solutions of erythromycin and tylosin, the detection limit of the assay was 0.2 ng mL(-1) determined to be for erythromycin and 2.0 ng mL(-1) for tylosin, while the sensitivity (25% inhibition concentration) was 1.0 ng mL(-1) for erythromycin and 3.0 ng mL(-1) for tylosin. The suitability of the assay for quantification of erythromycin and tylosin in bovine muscle was also studied. Spiked and real samples were analysed using the immunosensor system developed here. The ELISA showed precision values (relative standard deviation, RSD%) ranging from 4 to 9% for erythromycin and from 8 to 15% for tylosin; the accuracy (relative error, RE%) ranged from -11 to 6% and from -4 to 12% for erythromycin and tylosin, respectively. Results obtained on real samples were confirmed by micro-liquid chromatography coupled on line with tandem mass spectrometry (micro-LC-MS-MS), using an atmospheric pressure ionisation (API) source and an ionspray (IS) interface. The latter provides unequivocal identification and quantification of the analytes at the level of interest.

Animals↗

PubMed2003

Prussian Blue based screen printed biosensors with improved characteristics of long-term lifetime and pH stability.

The promising advantages of Prussian Blue (PB) as catalyst and of the thick film screen printing technology have been combined to assemble sensors with improved characteristics for the amperometric determination of H(2)O(2). PB-modified screen printed electrodes were applied to detect H(2)O(2) at an applied potential of -0.05 V versus the internal screen printed Ag pseudoreference electrode, showing a detection limit of 10(-7) mol l(-1), a linearity range from 10(-7) to 5x10(-5) mol l(-1), a sensitivity of 234 microA mmol l(-1) cm(-2), and a high selectivity. Improved stability at alkaline pH values was also observed, which made possible their use with enzymes having an optimum basic pH. Then, the immobilisation of a single enzyme (glucose oxidase (GOD) or choline oxidase (ChOX)) or of two enzymes, acetylcholinesterase (AchE) coimmobilised with ChOX, has been performed on the surface of PB modified screen-printed electrodes (SPEs) using glutaraldehyde and Nafion. ChOX has been selected as an example of enzyme working at alkaline pH. The choline biosensors showed a detection limit of 5x10(-7) mol l(-1), a wide linearity range (5x10(-7)-10(-4) mol l(-1)), a high selectivity and a remarkable long term stability of 9 months at 4 degrees C, and at least 4 weeks at room temperature. Similar analytical characteristics and stability were observed with the acetylcholine biosensors.

Biosensing Techniques↗

PubMed2002

Production of antibodies and development of highly sensitive formats of enzyme immunoassay for saxitoxin analysis.

In this paper the production of antibodies against saxitoxin (STX) is described, as is the optimization and comparison of two competitive ELISA formats (direct and indirect) for the detection of this toxin. Tests were performed in a 96-well microplate using the toxin-specific polyclonal antibodies produced in our laboratory, obtained from rabbits immunized with saxitoxin-keyhole limpet hemocyanin (STX-KLH). In indirect ELISA format saxitoxin, conjugated to bovine serum albumin (STX-BSA) was coated onto the microtitre plate and incubated with standard toxin and anti-STX antibody. A goat anti-rabbit IgG Peroxidase conjugate was used to enable detection. In the direct ELISA format, STX standard, STX conjugate to horseradish peroxidase (STX-HRP), and enzyme substrate/chromogen solution were sequentially added to the microplate after antibody coating.Results showed the saxitoxin detection limit to be 3 and 10 pg mL(-1) for direct and indirect ELISA formats, respectively. The suitability of the assay for quantification of saxitoxin in mussels was also studied. Samples were spiked with saxitoxin before and after sample treatment to study the extraction efficiency and matrix effect, respectively. After treatment, samples were analysed at 1:1000 v/v dilution in PBS to minimize the matrix effect and to detect the regulatory limit of 40-80 micro g saxitoxin per 100 g mussels as stipulated by the Food and Drug Administration. The efficiency of extraction of saxitoxin was from 72 to 102%. These data were confirmed by liquid chromatography coupled with fluorimetric detection, the technique currently used for quantitative determination of toxins in seafood.

Animals↗

PubMed2002

Modulation of viscero-somatic H-reflex during bladder filling: a possible tool in the differential diagnosis of neurogenic voiding dysfunctions.

OBJECTIVE: Despite evidence that the activation of visceral afferents modulates spinal motoneurone activity in humans, the circuits responsible for this modulation remain unclear. The aim of the present study was to assess the effect of urinary bladder filling on the excitability of somatic spinal motoneurones in patients affected by overactive bladder secondary to neurogenic and non-neurogenic causes in both patients with bladder underactivity and normal subjects by means of a urodynamic evaluation. METHODS: In order to evaluate the influence of bladder filling on somatic reflexes, we studied the H-reflex evoked by electrical stimuli applied to the tibial nerve at the popliteal fossa and recorded from the soleus muscle. The H-reflex was tested in the following conditions: (1). empty bladder; (2). medium bladder filling; (3). maximum bladder filling; (4). five minutes after bladder emptying. The H-reflex amplitude at empty bladder was considered as the control value. RESULTS: In healthy subjects, we observed a progressive reduction in the H-reflex amplitude during bladder filling. In spinal cord-injured patients affected by a neurogenic overactive bladder, bladder filling failed to inhibit the H-reflex amplitude; a decrease in the H-reflex amplitude similar to that displayed by normal subjects was observed in patients with a non-neurogenic overactive bladder. By contrast, H-reflex behavior was unmodified in neurogenic underactive bladder patients and was similar to normal subjects in psychogenic underactive patients. CONCLUSIONS: As behavior of the H-reflex varies during bladder filling in neurogenic and non-neurogenic overactive bladder patients as well as in neurogenic and non-neurogenic underactive bladder patients, H-reflex modulation may be considered a useful tool in the differential diagnosis of voiding dysfunctions.

Adult↗

PubMed2002

An electrochemical ELISA procedure for the screening of 17beta-estradiol in urban waste waters.

A sensitive electrochemical enzyme-linked immunosorbent assay (ELISA) has been used for the detection of 17beta-estradiol in waste waters. The activity of the label enzyme (horseradish peroxidase) was measured electrochemically using 3,3',5,5'-tetramethylbenzidine as electrochemical substrate. The detection limit was estimated to be 5 pg mL(-1), interday and intraday precision (RSD), ranged from 1 to 3% and from 3 to 6%, respectively. Analysis of waste waters from three different treatment plants demonstrated no matrix effect both for samples diluted 1:1 in buffer and diethyl ether extracted. Data on 36 samples analysed by an LC-ESI-MS-MS procedure and by the electrochemical ELISA assay were compared. Results correlated well. The electrochemical enzyme immunoassay appears suitable as a screening tool for analysis of estradiol in waste waters.

Electrochemistry↗