Elucidation of carotenoid patterns in citrus products by means of comprehensive normal-phase x reversed-phase liquid chromatography

A novel approach for carotenoid analysis has been developed. Orange essential oil and juice carotenoids were separated by means of comprehensive dual-gradient elution HPLC, using normal phase with a microbore silica column in the first dimension (first D), reversed phase with a monolithic C18 column in the second dimension (second D), and a 10-port switching valve as an interface. An on-line photodiode array detector was used in order to obtain absorption spectra. Peak identification was obtained by combining retention data with the UV-visible spectra.     

Desorption and ionization mechanisms in desorption atmospheric pressure photoionization

The factors influencing desorption and ionization in newly developed desorption atmospheric pressure photoionization-mass spectrometry (DAPPI-MS) were studied. Redirecting the DAPPI spray was observed to further improve the versatility of the technique: for dilute samples, parallel spray with increased analyte signal was found to be the best suited, while for more concentrated samples, the orthogonal spray with less risk for contamination is recommended. The suitability of various spray solvents and sampling surface materials was tested for a variety of analytes with different polarities and molecular weights. As in atmospheric pressure photoionization, the analytes formed [M + H](+), [M - H](-), M(+*), M(-*), [M - H + O](-), or [M - 2H + 2O](-) ions depending on the analyte, spray solvent, and ionization mode. In positive ion mode, anisole and toluene as spray solvents promoted the formation of M(+*) ions and were therefore best suited for the analysis of nonpolar compounds (anthracene, benzo[a]pyrene, and tetracyclone). Acetone and hexane were optimal spray solvents for polar compounds (MDMA, testosterone, and verapamil) since they produced intensive [M + H](+) ion peaks of the analytes. In negative ion mode, the type of spray solvent affected the signal intensity, but not the ion composition. M(-*) ions were formed from 1,4-dinitrobenzene, and [M - H + O](-) and [M - 2H + 2O](-) ions from 1,4-naphthoquinone, whereas acidic compounds (naphthoic acid and paracetamol) formed [M - H](-) ions. The tested sampling surfaces included various materials with different thermal conductivities. The materials with low thermal conductivity, i.e., polymers like poly(methyl methacrylate) and poly(tetrafluoroethylene) (Teflon) were found to be the best, since they enable localized heating of the sampling surface, which was found to be essential for efficient analyte desorption. Nevertheless, the sampling surface material did not affect the ionization mechanisms.     

The effect of tenderizing acids on linoleic acid oxidation during marination of pork

The oxidation of lipids in different prefabricated meat products may have detrimental effects on the organoleptic properties and/or safety of meat, and poses a serious health concern. The oxidation processes may be accelerated by acids that are added to some products, e.g., marinated meat. In this work, the oxidation of free polyunsaturated fatty acids during pork marination in the presence of different acidifiers was investigated. It was demonstrated by the measurement of thiobarbituric acid reactive substances (TBARS) and by liquid chromatography - tandem mass spectroscopy that the highest degree of oxidation occurred in acetic acid and lactic acid marinades, whereas the oxidation was significantly suppressed by citric and ascorbic acids. Among the primary products of oxidation, 9,12,13-trihydroxy-10-octadecenoic acid and two isomers of hydroxy-epoxy-octadecenoic acid were dominating. A nearly linear correlation between TBARS values and total content of these two hydroxy-fatty acids was observed.     

Development of an Efficient Acid Digestion Procedure Utilizing High-Pressure Asher Technique for the Determination of Iodine and Metallic Elements in Milk Powder

An effective wet digestion procedure for the determination of total iodine contents in milk powder samples was developed utilizing a high-pressure asher technique. The optimized method based on a two-stage digestion procedure. In the first stage, 500 mg samples were digested at 300 °C for 2 h using 15.2 mol L^?1 HNO₃ (5 mL) and 30 % H₂O₂ (3 mL). After the first digestion stage, digestion vessels were allowed to cool down and 1.2 mL of 20 % (w/v) Na₂S₂O₈ solution was added as an additional oxidizing agent to the samples. After that, the vessels were closed, and they were heated at 100 °C for 30 min, resulting in clear and colorless sample solutions. Iodine concentrations in the digested samples were measured with inductively coupled plasma mass spectrometry. The accuracy of the optimized method was confirmed by analyzing milk powder reference material (BCR-151, milk powder). The obtained value for iodine (5.29?±?0.37 mg kg^?1, n?=?6) was in good agreement with the certified value (5.35?±?0.14 mg kg^?1). Furthermore, the results obtained for reference material showed that the developed method can be applied also for the determination of other elements, e.g., copper, iron, and lead in the digested milk powder samples.     

In vitro fermentation of cereal dietary fibre carbohydrates by probiotic and intestinal bacteria

A range of probiotic and other intestinal bacteria were examined for their ability to ferment the dietary fibre carbohydrates β‐glucan, xylan, xylo‐oligosaccharides (XOS) and arabinoxylan. β‐Glucan was fermented by Bacteroides spp and Clostridium beijerinckii but was not fermented by lactobacilli, bifidobacteria, enterococci or Escherichia coli. Unsubstituted xylan was not fermented by any of the probiotic bacteria examined. However, many Bifidobacterium species and Lactobacillus brevis were able to grow to high yields using XOS. XOS were also efficiently fermented by some Bacteroides isolates but not by E coli, enterococci, Clostridium difficile, Clostridium perfringens or by the majority of intestinal Lactobacillus species examined. Bifidobacterium longum strains were able to grow well using arabinoxylan as the sole carbon source. These organisms hydrolysed and fermented the arabinosyl residues from arabinoxylan but did not substantially utilise the xylan backbone of the polysaccharide. Arabinoxylan was not fermented by lactobacilli, enterococci, E coli, C perfringens or C difficile and has potential to be an applicable carbohydrate to complement probiotic Bif longum strains in synbiotic combinations. © 2002 Society of Chemical Industry     

Characterization of Process Conditions in Industrial Stainless Steelmaking Electric Arc Furnace Using Optical Emission Spectrum Measurements

Emission spectroscopy is a potential method for gaining information on electric arc furnace (EAF) process conditions. Previous studies published in literature on industrial EAF emission spectra have focused on a smaller scales and DC arc furnaces. In this study emission spectrum measurements were conducted for 140t AC stainless steelmaking EAF at Outokumpu Stainless Oy, Tornio Works, Finland. Four basic types of emission spectra were obtained during the EAF process cycle. The first one is obscured by scrap steel, the second is dominated by thermal radiation of the slag, the third is dominated by alkali peaks and sodium D-lines and the fourth is characterized by multiple atomic emission peaks. The atomic emission peaks were identified by comparing them to the NIST database for atomic emission lines and previous laboratory measurements on EAF slag emission spectra. The comparison shows that the optic emission of an arc is dominated by slag components. Plasma conditions were analyzed by deriving plasma temperature from optical emissions of Ca I lines. The analysis suggests that accurate information on plasma conditions can be gained from outer plasma having a plasma temperature below 7000 K (6727 °C).     

Pedestrian Navigation Based on Inertial Sensors, Indoor Map, and WLAN Signals

As satellite signals, e.g. GPS, are severely degraded indoors or not available at all, other methods are needed for indoor positioning. In this paper, we propose methods for combining information from inertial sensors, indoor map, and WLAN signals for pedestrian indoor navigation. We present results of field tests where complementary extended Kalman filter was used to fuse together WLAN signal strengths and signals of an inertial sensor unit including one gyro and three-axis accelerometer. A particle filter was used to combine the inertial data with map information. The results show that both the map information and WLAN signals can be used to improve the pedestrian dead reckoning estimate based on inertial sensors. The results with different combinations of the available sensor information are compared.     

Roller-type gravure offset printing of conductive inks for high-resolution printing on ceramic substrates

The use of gravure offset printing methods at an industrial level requires a wide and deep knowledge of the printing properties of the inks. Novel hydrocarbon inks were developed with superior printing properties compared to alternative ethyl cellulose-based inks. There are principal behaviour properties of these inks that can be generally described. In particular, the resistance dependence of printed mass for single and multiprints and on the other hand, the effect of multiprinting on printed area smoothness and line height.

This article summarizes the results obtained and describes printing properties and defects: line widening, hair formation, ink flow from the gravure grooves, pinholes, image distortions, ribbing, scooping, streaking and gravure groove blocking. Three different printed samples were demonstrated, which are best suited for this manufacturing method: interdigital capacitor, inductor coil and laser soldering substrates.     

A New Field-Compatible Methodology for the Collection and Analysis of Fungal Fragments

A field-compatible collection system was developed and tested for the collection and analysis of fungal fragments. The new collection system consists of two types of Sharp-Cut cyclone samplers (PM _2.5 and PM _1.0 ) and an after-filter. Fungal particles are collected into three size fractions: (1) spores ( > 2.5 μ m); (2) a fragment-spore mixture (1.0–2.5 μ m); and (3) submicrometer-sized fragments ( < 1.0 μ m). The system was laboratory-tested using polystyrene latex (PSL) particles and particulate matter aerosolized from sporulating Aspergillus versicolor and Stachybotrys chartarum cultures. In addition to the particle count measured with direct-reading instruments, the (1 → 3)- β -D-glucan content in each size fraction was determined with the Limulus Amebocyte Lysate (LAL) assay.

Experiments conducted with PSL particles showed that the 50% cut-off values of the two cyclone samplers under the test conditions were 2.25 μ m and 1.05 μ m, respectively. No particle bounce onto the after-filter was observed when the total particle number entering the collection system was kept below 1.6 × 10 ⁸ . The (1 → 3)- β -D-glucan assay of samples aerosolized from both fungal species suggested that surface area is an important factor for determining the (1 → 3)- β -D-glucan content in the entire size-range of particles.

In conclusion, the new methodology is a promising tool for separating and analyzing fungal fragment samples.