University of North Florida
Browse the Citations
-OR-

Contact Info

Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

View Stuart Chalk's profile on LinkedIn

Marco Mascini

Abbrev:
Mascini, M.
Other Names:
Address:
Department of Public Health, Epidemiology and Analytical Chemistry, University of Florence, Via G. Capponi 9, 50121, Florence, Italy
Phone:
+39 55 275 7267
Fax:
+39 55 2476972

Citations 13

"Diamine Oxidase And Putrescine Oxidase Immobilized Reactors In Flow Injection Analysis: A Comparison In Substrate Specificity"
Talanta 1999 Volume 50, Issue 1 Pages 141-148
M. -A. Carsol and M. Mascini

Abstract: Enzyme reactors for the determination of biogenic amines have been developed using diamine oxidase (DAO) from porcine kidney and from lentil and putrescine oxidase (PUO) from microorganism (Micrococcus roseus). Determination is based on the electrochemical oxidation of enzymatically produced H2O2 at platinum electrode poised at 600 mV versus Ag/AgCl. The enzymes are immobilized on controlled pore glass beads activated by glutaraldehyde in a small reactor (diameter 5 mm, length 50 mm) and included in a flow injection analysis assembly. The reactor using DAO from porcine kidney as the biochemical component responds mainly to histamine (with a detection limit of 0.5 µM), and it can be used for the evaluation of fish spoilage. The PUO reactor shows a significant response only to putrescine. It is linear in the range 0.07-500 µM. The reactor using DAO from lentil is sensitive to several amines and it could be useful to evaluate a total value. The buffer used for both types of oxidase based sensors is phosphate 0.10 M pH 7.0 containing 0.10 M NaCl.
Derivatization

"Development Of A System With Enzyme Reactors For The Determination Of Fish Freshness"
Talanta 1998 Volume 47, Issue 2 Pages 335-342
M. -A. Carsol and M. Mascini*

Abstract: A continuous system for the determination of fish freshness with double enzyme reactors was developed and applied to the determination of the freshness indicator K K = 100(HxR + Hx)/(IMP + HxR + Hx), where IMP, HxR and Hx are Inosine monophosphate, Inosine and Hypoxanthine, respectively. The system was assembled with a three electrode screen-printed element (graphite as working electrode, silver as counter and silver, silver chloride as reference electrode) placed in a flow cell, a sample injection valve and two enzyme reactors. The determination of the total amt. of HxR and Hx is realized by flowing the sample through two reactors in series: one reactor was packed with nucleoside phosphorylase (Np) and the other with xanthine oxidase (XO) immobilized on aminopropyl glass. Similarly, the other term of the equation was evaluated by flowing through the two reactors the sample treated by Alkaline phosphatase (AlP) for 5-10 min at 45°C. One assay could be completed within 5 min. The system for the determination of fish freshness was reproducible within 2-3% (n = 4). The immobilized enzymes were fairly stable for at least three months at 4°C. More than 200-300 samples could be analyzed in about one month by using these enzyme reactors provided the disposable screen-printed electrode should be changed every 30-40 real samples. The results obtained suggest that the proposed sensor system provides a simple, rapid and economical method for the determination of fish freshness (K). We applied the present system with two reactors for the determination of K values in fish samples and compared the results with those obtained by the XO-reactor. Correlation factor and regression line between the two methods were 0.992 and Y = -3.14+1.03X respectively. We concluded that the present flow injection analysis (FIA) system with XO and Np reactors was suitable as a simple, easy to handle and reliable instrument for quality control in the fish industry.
Inosine monophosphate Inosine Hypoxanthine Marine Electrode Amperometry Electrode Aminopropyl glass Heated reaction Immobilized enzyme Quality

"Amperometric Detection Of Uric Acid And Hypoxanthine With Xanthine Oxidase Immobilized And Carbon Based Screen-printed Electrode"
Talanta 1997 Volume 44, Issue 11 Pages 2151-2159
M-A. Carsol, G. Volpe and M. Mascini*

Abstract: Carbon-based screen-printed electrodes are suitable for uric acid detection. Xanthine oxidase (XO) was immobilized either directly on the surface of the electrode or in a reactor with CPG aminopropylsilane in a FIA assembly. Higher reproducibility and lifetime was obtained with the reactor. Optimum conditions were found for the determination of Hypoxanthine (Hx), Inosine (HxR) and Inosine monophosphate (IMP). Calibration curves for IMP, HxR and Hx are linear up to 50 µM with detection limit of 1 µM for 50 µl injection. One assay is completed within 30 s. The reproducibility of 20 µM of Hx was obtained with CV 2%.
Uric acid Hypoxanthine Food Marine Electrode Electrode Amperometry Immobilized enzyme Controlled pore glass Optical isomers

"Urea Solid-state Biosensor Suitable For Continuous Dialysis Control"
Talanta 1996 Volume 43, Issue 8 Pages 1373-1377
S. Zamponi, B. Lo Cicero, M. Mascini*, L. Della Cianaband S. Sacco

Abstract: The sensor was fabricated by immobilizing a layer of PVC-nonactin solution in THF on a graphite electrode (preparation described) over which a layer of urease was immobilized with BSA and trifluoroacetaldehyde (schematic given). The biosensor was used in a flow cell or in a wall jet for FIA. Using a FIA system ultrafiltrated heparinized blood was injected into a carrier stream (0.8 ml/min) of phosphate buffer and the urea concentration was measured using the biosensor. The calibration graphs were prepared for 1-100 mM urea. The biosensor was stable up to 5 h in FIA.
Urea Blood Sensor Dialysis

"Determination Of Extra Virgin Olive Oil Acidity By FIA-titration"
Food Chem. 2001 Volume 73, Issue 2 Pages 235-238
Elisa Mariotti and Marco Mascini

Abstract: A direct determination of extra virgin olive oil acidity by an automated flow injection titration is proposed. The oil sample (280 µL) is directly injected, without dilution, in the carrier stream, a n-propanol solution flowing at 2 ml/min and containing potassium hydroxide 1 mM as titrant and phenolphthalein 5 10^-5 M as indicator. In the mixing chamber(1.5 mi) the sample mixes and reacts with the carrier stream. By an optical fiber beam, connected to a spectrophotometer set at 562 nm, we are able to appreciate continuously the phenolphthalein absorbance (Abs) decrease. The area of the peak Delta Abs vs, time has a linear correlation with the logarithm 1 of the sample acidity. Several extra virgin olive oil samples have been analyzed. The correlation curve between the official (O) and proposed methods (P) is P = (0.02±0.02) + (1.02±0.03)O, with r2 = 0.997 and s(r) = 0.033; the accuracy and precision, expressed as mean error and RSD, are both <5%; the number of samples analyzed per hour, the solvent and the sample consumption, in comparison with the official procedure, are respectively 12-60 versus 7-8, 2-10 mL versus 100-150 mL and 0.5 mL versus 10^-20 mL. These features and the simple procedure indicate how the proposed method could represent an interesting alternative to the European community official method for the determination of free fatty acids in oil. <(c)> 2001 Elsevier Science Ltd. All rights reserved.

"Electrochemical Sensor And Biosensor For Polyphenols Detection In Olive Oils"
Food Chem. 2000 Volume 71, Issue 4 Pages 553-562
Cecilia Capannesi, Ilaria Palchetti, Marco Mascini and Alessandro Parenti

Abstract: The aim of the work was to compare different techniques, in evaluating the phenolic content of an extra-virgin olive oil with varying storage time and storage conditions. A disposable screen-printed sensor (SPE) was coupled with differential pulse voltammetry (DPV) to determine the phenolic fractions after extraction with a glycine buffer; DPV parameters were chosen in order to study the oxidation peak of oleuropein, which was used as reference compound. A calibration curve of oleuropein was performed in glycine buffer 10 mM, pH = 2, NaCl 10 mM (D.L. = 0.25 ppm oleuropein, RSD = 7%). Moreover a tyrosinase based biosensor operating in organic solvent (hexane) was also assembled, using an amperometric oxygen probe as transducer. The calibration curves were realised using flow injection analysis (FIA) with phenol as the substrate (D.L. = 4.0 ppm phenol, RSD = 2%). Both of these methods are easy to operate, require no extraction (biosensor) or rapid extraction procedure (SPE), and the analysis time is short (min). The results obtained with these two innovative procedures were compared with a classical spectrophotometric assay using Folin-Ciocalteau reagent and HPLC analysis. Other extra-virgin olive oil quality parameters were investigated using classical methods in order to better define the alteration process and results are reported.

"NADH Electrochemical Sensor For The Enzymatic Determination Of L- And D-lactate And 3-hydroxybutyrate Using A Flow Injection Analysis"
Electroanalysis 1994 Volume 6, Issue 3 Pages 221-226
G. Marrazza, A. Cagnini, M. Mascini

Abstract: The NADH sensor was prepared from spectroscopic graphite (2 cm x 3 mm) assembled in a wall-jet cell using a FIA procedure and was coupled with enzyme reactors. The reactors were prepared by immobilizing L-, D-lactate or 3-hydroxybutyrate dehydrogenases on to aminopropyl-controlled pore glass beads using glutaraldehyde in a packed-bed enzyme reactor. Measurements were performed at an applied potential of +500 mV vs. Ag/AgCl. 3-hydroxybutyrate and L- and D-lactate were oxidized in the presence of NAD+ and the NADH produced was measured. By the appropriate choice of buffer, pH and NAD+ concentration, the analytes could be measured in the range 1 x 10^-6 to 1 x 10^-4 M in a few seconds. Calibration graphs are shown.
d-Lactate l-Lactate 3-hydroxybutyrate Biological Sensor Controlled pore glass

"Cholesterol Biosensors Prepared By Electropolymerization Of Pyrrole"
Electroanalysis 1993 Volume 5, Issue 9-10 Pages 753-763
Wolfgang Trettnak, Ilaria Lionti, Marco Mascini

Abstract: Platinum electrodes (1.75 mm diameter) were polished with alumina and rinsed thoroughly with water. Electropolymerization of cholesterol oxidase in pyrrole was carried out from a solution containing 10 mM NaClO4, 0.1 M pyrrole and 15-55 iu/ml of enzyme in 0.1 M phosphate buffer of pH 7, which was purged with N2 before applying a potential of 800 mV to the Pt electrode. The resulting biosensor was covered with a polycarbonate membrane (pore size 3 µm) and conditioned at 700 mV in 0.1 M phosphate buffer of pH 7. Measurements of cholesterol were carried out at 700 mV in the same buffer containing 1% of Triton X-100. The biosensor was applied in batch mode and in flow-through and flow injection analyzes with 1% Triton X-100 as carrier for detection of the H2O2 formed in the enzymatic reaction. In flow injection analysis with a 50 µL injection and a flow rate of 0.2 ml/min, the response was linear up to 250 µM-cholesterol; the detection limit was 5 µM and the sample throughput was 25/h. Interference by uric acid was fairly slight but that by ascorbic acid was severe.
Cholesterol Electrode Sensor Detector Interferences Triton X Surfactant

"Evaluation Of An FIA Operated Amperometric Bacterial Biosensor, Based On Pseudomonas Putida F1 For The Detection Of Benzene, Toluene, Ethylbenzene, And Xylenes (BTEX)"
Anal. Lett. 2005 Volume 38, Issue 10 Pages 1531-1547
Josef D. Rasinger; Giovanna Marrazza; Fabrizio Briganti; Andrea Scozzafava; Marco Mascini; A. P. F. Turner

Abstract: Recently, the development and optimization of a flow injection analysis (FIA) operated bacterial biosensor based on the aerobic catabolism of Pseudomonas putida ML2 was reported in the literature (Lanyon et al. 2004, 2005). By adapting information from these reports, we investigated whether operating parameters and procedures of the benzene biosensor could be directly applied to a new system based on a different bacterial strain for the detection of the whole benzene, toluene, ethylbenzene, and xylenes range. Cells of the investigated bacterial strain, Pseudomonas putida F1, were immobilized between two cellulose acetate membranes and fixed onto a Clark dissolved oxygen electrode. The P. putida F1 aerobically degrades benzene, toluene, and ethylbenzene (BTE) (Cho et al. 2000). The BTE biosensor in kinetic mode FIA displayed a linear range of 0.02-0.14 mM benzene (response time: 5 min, baseline recovery time: 15 min), 0.05-0.2 mM toluene (response time: 8 min, baseline recovery time: 20 min), and 0.1-0.2 mM ethylbenzene (response time: 12 min, baseline recovery time: 30 min), respectively. Due to the differences in sensitivity, response, and baseline recovery times for BTE, it was possible to differentiate each compound in mixtures of these volatile organic compounds (VOCs). No response for xylenes could be obtained since they cannot be completely metabolized by this bacterial strain. However, it was reported that the range of compounds degradable by P. putida F1 can possibly be expanded by cultivating the cells on different carbon sources (Choi et al. 2003). The sensor showed good intra- and interassay reproducibility, and all obtained results were comparable with those reported in the literature. The demonstrated reproducibility and the simplicity and ease of use as well as the portability for in situ measurements indicates that the biosensor could be suitable as a reliable initial warning device for elevated BTE levels in indoor and outdoor environments. Copyright © Taylor & Francis, Inc.

"Flow Injection Analysis Of Benzene Using An Amperometric Bacterial Biosensor"
Anal. Lett. 2004 Volume 37, Issue 8 Pages 1515-1528
Yvonne H. Lanyon, Giovanna Marrazza, Ibtisam E. Tothill, Marco Mascini

Abstract: A bacterial biosensor integrated within a flow injection analysis (FIA) system has been developed for the detection of benzene, based on its aerobic catabolism by Pseudomonas putida ML2. P. putida ML2 cells were immobilized between two cellulose acetate membranes and fixed onto a Clark dissolved oxygen electrode. Biosensor responses were investigated with the FIA system, resulting in a linear detection range between 0.01-0.1 mM benzene. A response and baseline recovery time of 6 and 10^-15 min, respectively, was obtained. A stable and reproducible sensor response has been found up to 28 days of use based on the same bacterial membrane, and the sensor has shown a high specificity to benzene, with a negligible response to other benzene-related compounds. Its ease of operation, rapid and sensitive response, and cost-effective production, demonstrate that the P. putida ML2 biosensor has potential applications for the analysis of samples containing benzene. The optimization of the biosensor-flow injection system is described.

"Piezoelectric Quartz Crystal Biosensor As A Direct Affinity Sensor"
Anal. Lett. 1994 Volume 27, Issue 8 Pages 1475-1487
Minunni, M.;Skladal, P.;Mascini, M.

Abstract: AT-cut piezoelectric quartz crystals with a basic resonant frequency of 10 MHz were fixed inside a flow-through thin-layer cell (30 µL) with one electrode in contact with the flowing liquid (70 µL/min); the crystal electrodes were connected to the detector (PZ 106; Universal Sensors, New Orleans, LA, USA). Adsorption of human IgG onto the Au electrode of the crystal was investigated. Measurements were performed in the continuous-flow mode using electrodes that had been treated sequentially with 1.2N-NaOH (20 min), water, 1.2N-HCl (5 min), concentrated HCl (2 min), then washed and dried in air. A graph of resonant frequency shifts for protein concentrations of 1 µg/ml to 10 mg/ml is shown; the analysis time was 5 h. The binding of mAb to 2,4-dichlorophenoxyacetic acid (2,4-D) immobilized onto the electrodes was also studied. The 2,4-D was activated with tributylamine and isobutylchloroformiate in dioxane, and immobilized with BSA onto γ-aminopropyltriethoxysilane-treated electrodes using glutaraldehyde (details given). The affinity reacton occurred in 10 min. A similar method was applied to determine 2,4-D in tap water.
Immunoglobulin G 2,4-dichlorophenoxyacetic acid Biological Water Electrode Sensor

"Electrochemical Biosensors For Biogenic Amines: A Comparison Between Different Approaches"
Anal. Chim. Acta 1998 Volume 358, Issue 3 Pages 277-284
S. Tombelli and M. Mascini*

Abstract: Diaminase oxidase (DAO) has been examined in order to obtain a sensor for biogenic amines; the enzyme was immobilized directly on the surface of a platinum electrode, posed at +700 mV vs. Ag/AgCl, or immobilized on glass beads in a small reactor (diameter 2 mm, length 40 mm) and included in a flow injection analysis assembly. Moreover, it was coupled with horseradish peroxidase coimmobilized and coupled with a glassy carbon electrode using ferrocene monocarboxylic acid as mediator dissolved in the carrier stream. Low detection limits were obtained in all cases with some differences; the selectivity was quite similar in the different assemblies. Moreover, we showed that selectivity can be changed using DAO, obtained from different starting materials not commercial available such as pea (Cicer arietinum).
Amines, biogenic Sensor Electrode Electrode Electrode Column Immobilized enzyme Selectivity

"Enzyme Immunoassay With Amperometric Flow Injection Analysis Using Horseradish Peroxidase As A Label. Application To The Determination Of Polychlorinated Biphenyls"
Anal. Chim. Acta 1996 Volume 336, Issue 1-3 Pages 167-174
Michele Del Carlo and Marco Mascini*

Abstract: An amperometric method for determining horseradish peroxidase (HRP) activity was developed using a flow injection system with H2O2/ferroceneacetic acid as substrate. The method was applied to an EIA for PCB. A microtitre plate was coated with 100 µl/well of 20 µg/ml PCB-gelatine conjugate in carbonate buffer of pH 9.6 for 16 h at 4°C. The plate was blocked with 1% skimmed milk and washed with PBS. The PCB sample or standard solution was incubated with 4 µg/ml anti-PCB IgG antibody (raised in chicken against a spectrum of PCB congeners) for 10 min and then 100 µL volumes were transferred to each cell. The competition reaction was allowed to proceed for 50 min and the plate was washed. The plate was incubated with HRP-labelled antibody for 1 h and washed. The substrate solution containing 1 mM H2O2 and 500 µM-ferroceneacetic acid of pH 7.5 was added and incubated for 30 min. The solution was analyzed by amperometric FIA using an injection volume of 5 µl, 100 mM phosphate buffer of pH 7.4 as the carrier stream (75 µl/min) and a vitreous C working electrode at -300 V vs. Ag/AgCl (Pt counter electrode). The dynamic range of the assay for Aroclor 1260 was 0.1-50 µg/ml and the RSD (n = 6) was
Biphenyl, derivatives, chloro Immunoassay Amperometry Electrode