Fast screening method for wine headspace compounds using solid-phase microextraction (SPME) and capillary GC technique

Solid-phase microextraction (SPME) coupled to capillary gas chromatography-mass spectrometry (GC-MS) was used for determination of volatile wine components. This combination offers a simple, quick, and sensitive approach suitable for characterization of wine aroma compounds without a complicated sample preparation procedure. Wines are characterized by "aromagrams", a set of identified components with corresponding relative abundances. Reproducibility (RSD errors of relative peak abundances) due to the analytical procedure are ca. 4%; variations among different samples of the same type of wine from the same region are ca. 8%. SPME-GC(-MS) has been shown to yield far larger differences among different wine types (Chardonnay, Muscat Ottonel, and Tramini) and among the same type of wine produced in different regions, showing the utility of the technique in wine analysis

Upravljanje otporno na kvarove modularnim prekidačko-reluktantnim strojem nadahnuto prirodom

Fault tolerance is an obligatory feature in safety critical applications (aeronautical, aerospace, medical and military applications, power plants, etc.), where loss of life, environmental disasters, equipment destructions or unplanned downtimes must be avoided. For such applications, a novel bio-inspired motion control system is proposed. All its three components (the switched reluctance machine, the power converter and the control system) are designed to be as fault tolerant as possible. This paper describes all these three fault tolerant components: the bio-inspired control system having self-healing capabilities, the power converter with an extra leg and the fault tolerant modular machine. The theoretical expectations and simulation results are validated by means of laboratory experiments.Otpornost na kvarove je nužnost u sigurnosno kritičnim aplikacijama (aeronautičke, zrakoplovne, medicinske i vojne aplikacije, elektrane itd.), gdje je potrebno izbjeći smrtne slučajeve, prirodne nepogode, uništenje opreme ili neplanirane prekide u radu. Za takve aplikacije, predložen je novi slijedni sustav nadahnut prirodom. Sve tri komponente (prekidačko-reluktantni stroj, pretvarač i sustav upravljanja) su projektirani da budu što je više moguće otporni na kvarove. Ovaj rad opisuje sve tri komponente: sustav upravljanja nadahnut prirodom sa samoliječećim svojstvima, pretvarač s dodatnom granom i modularni stroj otporan na kvarove. Teoretska očekivanja i simulacijski rezultati su provjereni laboratorijskim eksperimentima

Solid-phase microextraction: a powerful sample preparation tool prior to mass spectrometric analysis

Sample preparation is an essential step in analysis, greatly influencing the reliability and accuracy of resulted the time and cost of analysis. Solid-Phase Microextraction (SPME) is a very simple and efficient, solventless sample preparation method, invented by Pawliszyn in 1989. SPME has been widely used in different fields of analytical chemistry since its first applications to environmental and food analysis and is ideally suited for coupling with mass spectrometry (MS). All steps of the conventional liquid-liquid extraction (LLE) such as extraction, concentration, (derivatization) and transfer to the chromatograph are integrated into one step and one device, considerably simplifying the sample preparation procedure. It uses a fused-silica fibre that is coated on the outside with an appropriate stationary phase. The analytes in the sample are directly extracted to the fibre coating. The SPME technique can be routinely used in combination with gas chromatography, high-performance liquid chromatography and capillary electrophoresis and places no restriction on MS. SPME reduces the time necessary for sample preparation, decreases purchase and disposal costs of solvents and can improve detection limits. The SPME technique is ideally suited for MS applications, combining a simple and efficient sample preparation with versatile and sensitive detection. This review summarizes analytical characteristics and variants of the SPME technique and its applications in combination with MS

Examination of aroma production kinetics of different commercial wine yeasts in fermenting muscat ottonel wines with the help of SPME head-space sampling and fast GC analysys

Solid phase microextraction (SPME) coupled to fast capillary gas chromatography was used for monitoring the wine fermentation process. This combination offers a simple, quick and sensitive approach suitable for characterization of head-space components of wines during the fermentation process without a complicated sample preparation procedure. In this work this method was used to observe the differences in aroma production between three different commercial yeasts and the indigenous yeast flora

Concentration of liquid whole egg by membrane filtration

One of the most important enriching materials at the processing of alimentary pastes is the egg, which usage is limited because of its water content. Removing water from liquid whole egg with membrane processes, such as ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) was applied for raising the solid content at a temperature of 25 °C at constant flow rate. The separation procedures were carried out on laboratory scale equipments. The initial solid content of the liquid whole egg was 24 refractive (Ref%). The effects of different recirculation flow rates and transmembrane pressure differences were investigated on the permeate flux of the liquid egg. The product had up to 30, 35.5 and 36 Ref% solids in case of UF, NF and RO, respectively. From the resistance data it is obvious, that the polarization layer resistances (RP) determine the values of the permeate flux. The total solid content of permeate was 0.3 and 0.1 Ref% in case of nanofiltration and reverse osmosis, respectively. On the basis of experiments main data of a continuous pilot scale system were calculated and simplified cost estimation was performed using recent economic data of year 2011