OBJECTIVE: The aim of this study was to compare the visual assessment of tooth shade with the measurement using intraoral scanner (IOS) and spectrophotometer devices. METHODOLOGY: The colour for a single unit implant supported crown was measured visually, using IOS, and spectrophotometer. The results of the digital methods were compared with the visual measurement. RESULTS: A complete colour match with the visual measurement was in 42.9% of cases for IOS, and in 33.3% of cases for spectrophotometry. The match in the colour value, hue, and chroma were in 61.9%, 95.2%, and 66.7% of cases, respectively, for the IOS; and in 61.9%, 61.9%, and 66.7% of cases, respectively, for the spectrophotometry. The differences between the IOS and spectrophotometry were not statistically significant. CONCLUSIONS: The most reliable method for tooth colour selection is the visual measurement by an experienced dentist. IOS and spectrophotometer can be used as an alternative method, however in both cases they should be verified using visual measurement.

• MeSH
• Color MeSH
• Prosthesis Coloring * methods   MeSH
• Ceramics MeSH
• Spectrophotometry MeSH
• Color Perception * MeSH
• Publication type
• Journal Article MeSH

A device with four parallel channels was designed and manufactured by 3D printing in titanium. A simple experimental setup allowed splitting of the mobile phase in four parallel streams, such that a single sample could be analysed four times simultaneously. The four capillary channels were filled with a monolithic stationary phase, prepared using a zwitterionic functional monomer in combination with various dimethacrylate cross-linkers. The resulting stationary phases were applicable in both reversed-phase and hydrophilic-interaction retention mechanisms. The mobile-phase composition was optimized by means of a window diagram so as to obtain the highest possible resolution of dopamine precursors and metabolites on all columns. Miniaturized electrochemical detectors with carbon fibres as working electrodes and silver micro-wires as reference electrodes were integrated in the device at the end of each column. Experimental separations were successfully compared with those predicted by a three-parameter retention model. Finally, dopamine was determined in human urine to further confirm applicability of the developed device.

• MeSH
• Chromatography, Liquid instrumentation   MeSH
• Equipment Design MeSH
• Dopamine urine   MeSH
• Hydrophobic and Hydrophilic Interactions MeSH
• Humans MeSH
• Microelectrodes MeSH
• Microfluidic Analytical Techniques instrumentation   MeSH
• Titanium MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

The carbon fiber and silver microwire were used as working and pseudoreference electrode, respectively, and inserted into the ending of capillary to prepare monolithic capillary column with an integrated electrochemical detector. Prepared capillary devices offered stable and robust results with relative standard deviations of retention, resolution, and detection signal lower than 1.5, 5.5, and 5.0%, respectively. To further increase sensitivity of developed electrochemical microdetector, multiple pulse amperometry detection mode has been used. Optimized integrated device provided reliable chromatographic separation of mixture of neurotransmitters with calibration curve for dopamine linear from 0.5 to 20.0mgL-1 and an instrumental limit of detection as low as 24pg of injected dopamine. Finally, developed capillary column was applied to successful determination of dopamine in a human urine. By using both calibration curve and standard addition method, the dopamine level was determined to be 0.74±0.03mgL-1 and 0.71±0.02mgL-1, respectively. Triplicates of dopamine analysis provided relative standard deviations lower than 2.7% for intraday analyses, while interday relative standard deviations were lower than 3.6% for five consecutive days.

• MeSH
• Dopamine analysis   MeSH
• Electrochemical Techniques instrumentation   methods   MeSH
• Electrodes MeSH
• Humans MeSH
• Neurotransmitter Agents analysis   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Evaluation Study MeSH

In this work we have developed a hydrophilic poly(hydroxyethyl methacrylate-co-poly(ethylene glycol) diacrylate) cryogel placed in the centrifugal filter device. The composition of the polymerization mixture as well as the polymerization conditions were optimized in order to prepare a material with bimodal pore size distribution with 20-50 μm flow through macropores and submicrometer pores in the polymer walls. The optimized, mechanically stable, highly porous, material was used for spin column lectin chromatography. The surface of the monolithic scaffold was activated by epichlorohydrin and used for immobilization of concanavalin A to provide the affinity supports for selective isolation of glycoproteins containing high mannose glycan structures. The performance of the developed lectin modified cryogels was evaluated by analyses of glycoprotein mixtures. The efficiency and selectivity of the affinity supports were confirmed by MALDI-MS analysis.

• MeSH
• Chromatography, Liquid MeSH
• Glycoproteins chemistry   isolation & purification   MeSH
• Concanavalin A chemistry   MeSH
• Cryogels * MeSH
• Methacrylates chemistry   MeSH
• Polyethylene Glycols chemistry   MeSH
• Polymerization MeSH
• Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

On-line sample pretreatment (clean-up and analyte preconcentration) is for the first time coupled to sequential injection chromatography. The approach combines anion-exchange solid-phase extraction and the highly effective pentafluorophenylpropyl (F5) fused-core particle column for separation of eight sulfonamide antibiotics with similar structures (sulfathiazole, sulfanilamide, sulfacetamide, sulfadiazine, sulfamerazine, sulfadimidine, sulfamethoxazole and sulfadimethoxine). The stationary phase was selected after a critical comparison of the performance achieved by three fused-core reversed phase columns (Ascentis(®) Express RP-Amide, Phenyl-Hexyl, and F5) and two monolithic columns (Chromolith(®) High Resolution RP-18 and CN). Acetonitrile and acetate buffer pH 5.0 at 0.60 mL min(-1) were used as mobile phase to perform the separations before spectrophotometric detection. The first mobile phase was successfully used as eluent from SPE column ensuring transfer of a narrow zone to the chromatographic column. Enrichment factors up to 39.2 were achieved with a 500 µL sample volume. The developed procedure showed analysis time <10.5 min, resolutions >1.83 with peak symmetry ≤1.52, LODs between 4.9 and 27 µg L(-1), linear response ranges from 30.0 to 1000.0 µg L(-1) (r(2)>0.996) and RSDs of peak heights <2.9% (n=6) at a 100 µg L(-1) level and enabled the screening control of freshwater samples contaminated at the 100 µg L(-1) level. The proposed approach expanded the analytical potentiality of SIC and avoided the time-consuming batch sample pretreatment step, thus minimizing risks of sample contamination and analyte losses.

• MeSH
• Anti-Bacterial Agents analysis   isolation & purification   MeSH
• Water Pollutants, Chemical analysis   isolation & purification   MeSH
• Equipment Design MeSH
• Solid Phase Extraction instrumentation   MeSH
• Limit of Detection MeSH
• Flow Injection Analysis instrumentation   MeSH
• Rivers chemistry   MeSH
• Sulfonamides analysis   isolation & purification   MeSH
• Chromatography, High Pressure Liquid instrumentation   MeSH
• Publication type
• Journal Article MeSH
• Evaluation Study MeSH
• Research Support, Non-U.S. Gov't MeSH

A novel approach for automation of Micro-Extraction by Packed Sorbent (MEPS), a solid phase extraction technique, is presented, enabling precise and repeatable liquid handling due to the employment of sequential injection technique. The developed system was used for human urine sample clean-up and pre-concentration of betaxolol before its separation and determination. A commercial MEPS C-18 cartridge was integrated into an SIChrom™ system. The chromatographic separation was performed on a monolithic High Resolution C18 (50×4.6 mm) column which was coupled on-line in the system with Micro-Extraction using an additional selection valve. A mixture of acetonitrile and aqueous solution of 0.5% triethylamine with acetic acid, pH adjusted to 4.5 in ratio 30:70 was used as a mobile phase for elution of betaxolol from MEPS directly onto the monolithic column where the separation took place. Betaxolol was quantified by a fluorescence detector at wavelengths λ(ex)=220 nm and λ(em)=305 nm. The linear calibration range of 5-400 ng mL(-1), with limit of detection 1.5 ng mL(-1) and limit of quantification 5 ng mL(-1) and correlation r=0.9998 for both the standard and urine matrix calibration were achieved. The system recovery was 105±5%; 100±4%; 108±1% for three concentration levels of betaxolol in 10 times diluted urine - 5, 20 and 200 ng mL(-1), respectively.

• MeSH
• Urinalysis instrumentation   methods   MeSH
• Betaxolol isolation & purification   urine   MeSH
• Chromatography methods   MeSH
• Equipment Design MeSH
• Spectrometry, Fluorescence MeSH
• Injections * MeSH
• Humans MeSH
• Solid Phase Microextraction methods   MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

• MeSH
• Lasers MeSH
• Publication type
• Meeting Abstract MeSH
• Collected Work MeSH

• Conspectus
• Optika
• NML Fields
• fyzika, biofyzika
• technika