A fully automated sequential injection system was tested in terms of its application in liberation testing, and capabilities and limitations were discussed for clotrimazole liberation from three semisolid formulations. An evaluation based on kinetic profiles obtained in short and longer sampling intervals and steady-state flux values were applied as traditional methods. The obtained clotrimazole liberation profile was faster in the case of Delcore and slower for Clotrimazol AL and Canesten cream commercial formulations. The steady-state flux values for the tested formulations were 52 µg cm-2 h-1 for Canesten, 35 µg cm-2 h-1 for Clotrimazol AL, and 7.2 µg cm-2 h-1 for Delcore measured in 4 min sampling intervals. A simplified approach for the evaluation of the initial rate based on the gradient between the second and third sampling points was used for the first time and was found to correspond well with the results of the conventional methods. A comparison based on the ratio of the steady-state flux and the initial rate values for Canesten and Clotrimazol AL proved the similarity of the obtained results. The proposed alternative was successfully implemented for the comparison of short-term kinetic profiles. Consequently, a faster and simpler approach for dissolution/liberation testing can be used.

• Keywords
• Franz cell, clotrimazole, kinetic profile, liberation study, sequential injection analysis,
• MeSH
• Antifungal Agents analysis   MeSH
• Kinetics MeSH
• Clotrimazole analysis   MeSH
• Automation, Laboratory methods   MeSH
• Skin Cream MeSH
• Drug Compounding MeSH
• Flow Injection Analysis methods   MeSH
• Drug Liberation MeSH
• Publication type
• Journal Article MeSH
• Evaluation Study MeSH
• Names of Substances
• Antifungal Agents MeSH
• Clotrimazole MeSH

A new method for the simultaneous determination of two tumour biomarkers, homovanillic (HVA) and vanillylmandelic acid (VMA), using flow injection analysis (FIA) with amperometric detection (AD) at a commercially available boron doped diamond electrode (BDDE) was developed. It was found that this method is suitable for the determination of HVA (in the presence of VMA) and VMA (in the presence of HVA) in optimum medium of Britton-Robinson buffer (0.04 mol L-1, pH 3.0). Calibration dependences consist of two linear parts for both biomarkers, the first one being in the concentration range from 1 to 10 μmol L-1 and the second one from 10 to 100 μmol L-1 (with obtained LODs 0.44 μmol L-1 for HVA and 0.34 μmol L-1 for VMA, respectively). To minimize any negative effects related to the passivation of the working electrode, suitable cleaning pulses (+2.4 V for 30 s) were imposed on the working electrode after each measurement. An attempt to use FIA with multiple pulse amperometric detection to determine both analytes in one run was not successful. Changing potentials in short intervals in multiple pulse detection probably results in mutual interaction of analytes and/or products of their electrochemical oxidation, thus preventing the application of this approach.

• Keywords
• Boron doped diamond electrode, Flow injection analysis, Homovanillic acid, Tumour biomarkers, Vanillylmandelic acid,
• MeSH
• Boron chemistry   MeSH
• Diamond chemistry   MeSH
• Electrochemical Techniques instrumentation   methods   MeSH
• Electrodes MeSH
• Homovanillic Acid analysis   chemistry   MeSH
• Vanilmandelic Acid analysis   chemistry   MeSH
• Limit of Detection MeSH
• Biomarkers, Tumor analysis   chemistry   MeSH
• Oxidation-Reduction MeSH
• Flow Injection Analysis methods   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Boron MeSH
• Diamond MeSH
• Homovanillic Acid MeSH
• Vanilmandelic Acid MeSH
• Biomarkers, Tumor MeSH

An amperometric biosensor compatible with a flow injection analysis (FIA) for highly selective determination of acetaminophen (APAP) in a sample of human urine was developed. This biosensor is also suitable for use in the routine pharmaceutical practice. To prove this statement, two different commercially available pharmaceutical formulations were analyzed. This nano-(bio)electroanalytical device was made from a commercially available screen-printed carbon electrode covered by a thin layer of non-functionalized graphene (NFG) as amperometric transducer. A biorecognition layer was prepared from mushroom (Agaricus bisporus) tyrosinase (EC 1.14.18.1) cross-linked using glutaraldehyde, where resulting aggregates were covered by Nafion®, a known ion exchange membrane. Owing to the use of tyrosinase and presence of NFG, the developed analytical instrument is able to measure even at potentials of 0 V. Linear ranges differ according to choice of detection potential, namely up to 130 μmol L-1 at 0 V, up to 90 μmol L-1 at -0.1 V, and up to 70 μmol L-1 at -0.15 V. The first mentioned linear range is described by the equation Ip [μA] = 0.236 - 0.1984c [μmol L-1] and correlation coefficient r = 0.9987; this equation was used to quantify the content of APAP in each sample. The limit of detection of APAP was estimated to be 1.1 μmol L-1. A recovery of 96.8% (c = 25 μmol L-1, n = 5 measurements) was calculated. The obtained results show that FIA is a very selective method for APAP determination, being comparable to the chosen reference method of reversed-phase high-performance liquid chromatography.

• Keywords
• Acetaminophen, Amperometry, Biosensor, Flow injection analysis, Human urine, Tyrosinase,
• MeSH
• Agaricus enzymology   MeSH
• Urinalysis instrumentation   methods   MeSH
• Biosensing Techniques instrumentation   methods   MeSH
• Equipment Design MeSH
• Humans MeSH
• Limit of Detection MeSH
• Analgesics, Non-Narcotic urine   MeSH
• Acetaminophen urine   MeSH
• Flow Injection Analysis instrumentation   methods   MeSH
• Monophenol Monooxygenase chemistry   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Evaluation Study MeSH
• Names of Substances
• Analgesics, Non-Narcotic MeSH
• Acetaminophen MeSH
• Monophenol Monooxygenase MeSH

A fully automated method for the determination of lovastatin in dietary supplements containing red yeast rice has been developed. It uses a sequential injection analysis system combined with solid-phase extraction applying highly selective molecularly imprinted polymer sorbent. A miniaturized column for on-line extraction was prepared by packing 4.5 mg of the sorbent in a 5.0 × 2.5-mm-i.d. cartridge, which was used in the flow manifold. Sequential injection analysis manifold enabled all steps of lovastatin extraction and continuous spectrophotometric detection at 240 nm. A limit of detection of 60 μg g-1, a limit of quantitation of 200 μg g-1, and a linear calibration range of 200-2000 μg g-1 were achieved. Intra-day and inter-day precision values (RSD) were ≤ 6.7% and ≤ 4.9%, respectively, and method recovery values of spiked red yeast rice extracts at 200, 1000, and 2000 μg g-1 concentration levels were 82.9, 95.2, and 87.7%. Our method was used for determination of lovastatin lactone in four dietary supplements containing red yeast rice as a natural source of lovastatin, also known as monacolin K. The extracted samples were subsequently analyzed by the reference UHPLC-MS/MS method. Statistical comparison of results (F test, t test, α = 0.05) obtained by both methods did not reveal significant difference. A substantial advantage of the new automated approach is high sample throughput thanks to the analysis time of 7.5 min, miniaturization via down-scaling the extraction column, and smaller sample and solvent consumption, as well as reduced generation of waste. Graphical abstract ᅟ.

• Keywords
• Dietary supplements, Lovastatin, Molecularly imprinted polymer, On-line solid-phase extraction, Sequential injection analysis,
• MeSH
• Anticholesteremic Agents analysis   MeSH
• Biological Products analysis   MeSH
• Equipment Design MeSH
• Solid Phase Extraction instrumentation   methods   MeSH
• Limit of Detection MeSH
• Lovastatin analysis   MeSH
• Molecular Imprinting instrumentation   methods   MeSH
• Polymers chemistry   MeSH
• Dietary Supplements analysis   MeSH
• Flow Injection Analysis instrumentation   methods   MeSH
• Spectrophotometry, Ultraviolet instrumentation   methods   MeSH
• Tandem Mass Spectrometry instrumentation   methods   MeSH
• Chromatography, High Pressure Liquid instrumentation   methods   MeSH
• Publication type
• Journal Article MeSH
• Validation Study MeSH
• Names of Substances
• Anticholesteremic Agents MeSH
• Biological Products MeSH
• Lovastatin MeSH
• Polymers MeSH
• red yeast rice MeSH Browser

The development of capacitively coupled contactless conductivity detection for the two-year period from mid-2014 to mid-2016 is covered in this review. This includes a survey of fundamental studies and further developments of the measuring technique reported as well as a discussion of new applications. These mostly concern capillary electrophoresis carried out in conventional capillaries as well as on microchip electrophoresis devices. The main focus is on the determination of small non-UV-absorbing organic ions and inorganic ions in different types of samples of clinical, nutritional or environmental interest. Outside of electrophoresis contactless conductivity detection is finding uses in detection in column chromatography, flow-injection analysis and industrial applications.

• Keywords
• Capacitively coupled contactless conductivity detection, Capillary electrophoresis, Microchip electrophoresis, Review,
• MeSH
• Inorganic Chemicals analysis   MeSH
• Chromatography methods   MeSH
• Equipment Design MeSH
• Electric Conductivity MeSH
• Electrodes MeSH
• Electrophoresis, Capillary instrumentation   methods   MeSH
• Electrophoresis, Microchip instrumentation   methods   MeSH
• Ions analysis   MeSH
• Humans MeSH
• Organic Chemicals analysis   MeSH
• Computer Simulation MeSH
• Flow Injection Analysis methods   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Inorganic Chemicals MeSH
• Ions MeSH
• Organic Chemicals MeSH

A novel flow-programming setup based on the sequential injection principle is herein proposed for on-line monitoring of temporal events in cell permeation studies. The permeation unit consists of a Franz cell with its basolateral compartment mixed under mechanical agitation and thermostated at 37 °C. The apical compartment is replaced by commercially available Transwell inserts with a precultivated cell monolayer. The transport of drug substances across epithelial cells genetically modified with the P-glycoprotein membrane transporter (MDCKII-MDR1) is monitored on-line using rhodamine 123 as a fluorescent marker. The permeation kinetics of the marker is obtained in a fully automated mode by sampling minute volumes of solution from the basolateral compartment in short intervals (10 min) up to 4 h. The effect of a P-glycoprotein transporter inhibitor, verapamil as a model drug, on the efficiency of the marker transport across the cell monolayer is thoroughly investigated. The analytical features of the proposed flow method for cell permeation studies in real time are critically compared against conventional batch-wise procedures and microfluidic devices.

• Keywords
• Fully automated system, P-glycoprotein transporter, Permeation study, Rhodamine 123, Sequential injection analysis,
• MeSH
• Automation methods   MeSH
• Biological Transport MeSH
• Epithelial Cells chemistry   metabolism   MeSH
• Kinetics MeSH
• Humans MeSH
• ATP Binding Cassette Transporter, Subfamily B, Member 1 metabolism   MeSH
• Flow Injection Analysis instrumentation   methods   MeSH
• Rhodamine 123 chemistry   metabolism   MeSH
• Verapamil chemistry   metabolism   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Evaluation Study MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• ATP Binding Cassette Transporter, Subfamily B, Member 1 MeSH
• Rhodamine 123 MeSH
• Verapamil MeSH

The review covers the progress of capacitively coupled contactless conductivity detection over the 2 years leading up to mid-2014. During this period many new applications for conventional CE as well as for microchip separation devices have been reported; prominent areas have been clinical, pharmaceutical, forensic, and food analyses. Further progress has been made in the development of field portable instrumentation based on CE with contactless conductivity detection. Several reports concern the combination with sample pretreatment techniques, in particular electrodriven extractions. Accounts of arrays of contactless conductivity detectors have appeared, which have been created for quite different tasks requiring spatially resolved information. The trend of the use of contactless conductivity measurements for applications other than CE has continued.

• Keywords
• Capacitively coupled contactless conductivity detection, Capillary electrophoresis, Microchip electrophoresis,
• MeSH
• Food Analysis instrumentation   methods   MeSH
• Equipment Design MeSH
• Electric Conductivity MeSH
• Electrophoresis, Capillary instrumentation   methods   MeSH
• Electrophoresis, Microchip instrumentation   methods   MeSH
• Humans MeSH
• Environmental Monitoring instrumentation   methods   MeSH
• Flow Injection Analysis instrumentation   methods   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH

In this work, an application of an enzymatic reaction for the determination of the highly hydrophobic drug propofol in emulsion dosage form is presented. Emulsions represent a complex and therefore challenging matrix for analysis. Ethanol was used for breakage of a lipid emulsion, which enabled optical detection. A fully automated method based on Sequential Injection Analysis was developed, allowing propofol determination without the requirement of tedious sample pre-treatment. The method was based on spectrophotometric detection after the enzymatic oxidation catalysed by horseradish peroxidase and subsequent coupling with 4-aminoantipyrine leading to a coloured product with an absorbance maximum at 485 nm. This procedure was compared with a simple fluorimetric method, which was based on the direct selective fluorescence emission of propofol in ethanol at 347 nm. Both methods provide comparable validation parameters with linear working ranges of 0.005-0.100 mg mL(-1) and 0.004-0.243 mg mL(-1) for the spectrophotometric and fluorimetric methods, respectively. The detection and quantitation limits achieved with the spectrophotometric method were 0.0016 and 0.0053 mg mL(-1), respectively. The fluorimetric method provided the detection limit of 0.0013 mg mL(-1) and limit of quantitation of 0.0043 mg mL(-1). The RSD did not exceed 5% and 2% (n=10), correspondingly. A sample throughput of approx. 14 h(-1) for the spectrophotometric and 68 h(-1) for the fluorimetric detection was achieved. Both methods proved to be suitable for the determination of propofol in pharmaceutical formulation with average recovery values of 98.1 and 98.5%.

• Keywords
• 4-Aminoantipyrine, Emulsions, Horseradish peroxidase, Propofol, Sequential Injection Analysis,
• MeSH
• Ampyrone metabolism   MeSH
• Automation MeSH
• Fluorescence MeSH
• Fluorometry methods   MeSH
• Indicators and Reagents metabolism   MeSH
• Horseradish Peroxidase metabolism   MeSH
• Propofol analysis   MeSH
• Flow Injection Analysis methods   MeSH
• Spectrophotometry, Ultraviolet methods   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Ampyrone MeSH
• Indicators and Reagents MeSH
• Horseradish Peroxidase MeSH
• Propofol MeSH

A proof of concept of a novel pervaporation sequential injection (PSI) analysis method for automatic non-chromatographic speciation analysis of inorganic arsenic in complex aqueous samples is presented. The method is based on hydride generation of arsine followed by its on-line pervaporation-based membrane separation and CCD spectrophotometric detection. The concentrations of arsenite (As(III)) and arsenate (As(V)) are determined sequentially in a single sample zone. The leading section of the sample zone merges with a citric acid/citrate buffer solution (pH 4.5) for the selective reduction of As(III) to arsine while the trailing section of the sample zone merges with hydrochloric acid solution to allow the reduction of both As(III) and As(V) to arsine at pH lower than 1. Virtually identical analytical sensitivity is obtained for both As(III) and As(V) at this high acidity. The flow analyzer also accommodates in-line pH detector for monitoring of the acidity throughout the sample zone prior to hydride generation. Under optimal conditions the proposed PSI method is characterized by a limit of detection, linear calibration range and repeatability for As(III) of 22 μg L(-1) (3sblank level criterion), 50-1000 μg L(-1) and 3.0% at the 500 μg L(-1) level and for As(V) of 51 μg L(-1), 100-2000 μg L(-1) and 2.6% at the 500 μg L(-1) level, respectively. The method was validated with mixed As(III)/As(V) standard aqueous solutions and successfully applied to the determination of As(III) and As(V) in river water samples with elevated content of dissolved organic carbon and suspended particulate matter with no prior sample pretreatment. Excellent relative recoveries ranging from 98% to 104% were obtained for both As(III) and As(V).

• Keywords
• Hydride generation, Inorganic arsenic, Pervaporation, Sequential injection analysis, Speciation,
• MeSH
• Arsenates isolation & purification   MeSH
• Arsenicals chemistry   MeSH
• Arsenites isolation & purification   MeSH
• Water Pollutants, Chemical isolation & purification   MeSH
• Calibration MeSH
• Hydrogen-Ion Concentration MeSH
• Citric Acid chemistry   MeSH
• Limit of Detection MeSH
• Flow Injection Analysis methods   MeSH
• Rivers chemistry   MeSH
• Spectrophotometry instrumentation   methods   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• arsenic acid MeSH Browser
• Arsenates MeSH
• Arsenicals MeSH
• Arsenites MeSH
• arsenite MeSH Browser
• arsine MeSH Browser
• Water Pollutants, Chemical MeSH
• Citric Acid MeSH

Currently, the influenza virus infects millions of individuals every year. Since the influenza virus represents one of the greatest threats, it is necessary to develop a diagnostic technique that can quickly, inexpensively, and accurately detect the virus to effectively treat and control seasonal and pandemic strains. This study presents an alternative to current detection methods. The flow-injection analysis-based biosensor, which can rapidly and economically analyze a wide panel of influenza virus strains by using paramagnetic particles modified with glycan, can selectively bind to specific viral A/H5N1/Vietnam/1203/2004 protein-labeled quantum dots. Optimized detection of cadmium sulfide quantum dots (CdS QDs)-protein complexes connected to paramagnetic microbeads was performed using differential pulse voltammetry on the surface of a hanging mercury drop electrode (HMDE) and/or glassy carbon electrode (GCE). Detection limit (3 S/N) estimations based on cadmium(II) ions quantification were 0.1 μg/mL or 10 μg/mL viral protein at HMDE or GCE, respectively. Viral protein detection was directly determined using differential pulse voltammetry Brdicka reaction. The limit detection (3 S/N) of viral protein was estimated as 0.1 μg/mL. Streptavidin-modified paramagnetic particles were mixed with biotinylated selective glycan to modify their surfaces. Under optimized conditions (250 μg/mL of glycan, 30-min long interaction with viral protein, 25°C and 400 rpm), the viral protein labeled with quantum dots was selectively isolated and its cadmium(II) content was determined. Cadmium was present in detectable amounts of 10 ng per mg of protein. Using this method, submicrogram concentrations of viral proteins can be identified.

• MeSH
• Biosensing Techniques instrumentation   methods   MeSH
• Biotin chemistry   metabolism   MeSH
• Electrochemical Techniques instrumentation   methods   MeSH
• Electrodes MeSH
• Hemagglutinin Glycoproteins, Influenza Virus analysis   metabolism   MeSH
• Cadmium analysis   MeSH
• Quantum Dots MeSH
• Limit of Detection MeSH
• Linear Models MeSH
• Magnetite Nanoparticles chemistry   MeSH
• Flow Injection Analysis instrumentation   methods   MeSH
• Mercury chemistry   MeSH
• Cadmium Compounds chemistry   MeSH
• Streptavidin chemistry   metabolism   MeSH
• Sulfides chemistry   MeSH
• Carbon chemistry   MeSH
• Influenza A Virus, H5N1 Subtype chemistry   isolation & purification   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Biotin MeSH
• cadmium sulfide MeSH Browser
• Hemagglutinin Glycoproteins, Influenza Virus MeSH
• Cadmium MeSH
• Magnetite Nanoparticles MeSH
• Mercury MeSH
• Cadmium Compounds MeSH
• Streptavidin MeSH
• Sulfides MeSH
• Carbon MeSH