Single-run separation of closely related cationic and anionic compounds by CE-ESI-MS: application to the simultaneous analysis of melamine and its analogs in milk

In recent years, two adulteration incidents concerning the addition of melamine, a nitrogen-rich industrial small polar compound, to pet food and infant formula products have occurred in China. These issues prompted laboratories to develop methods for the analysis of melamine and related compounds in a wide variety of food products and ingredients. In this context, a CE-ESI-MS method was developed to simultaneously analyze melamine and its related products (ammeline, ammelide and cyanuric acid) that possess close physico-chemical properties. This method allows the simultaneous analysis of both cations and anions in a single run, using CE to divide the run into two time segments in normal polarity mode. For this purpose, ESI polarity was switched once during the run, increasing sensitivity and data quality. The method was applied to spiked powdered milk and melamine-contaminated powdered milk, with two sample preparation procedures

Single-run separation of closely related cationic and anionic compounds by CE-ESI-MS: application to the simultaneous analysis of melamine and its analogs in milk

In recent years, two adulteration incidents concerning the addition of melamine, a nitrogen-rich industrial small polar compound, to pet food and infant formula products have occurred in China. These issues prompted laboratories to develop methods for the analysis of melamine and related compounds in a wide variety of food products and ingredients. In this context, a CE-ESI-MS method was developed to simultaneously analyze melamine and its related products (ammeline, ammelide and cyanuric acid) that possess close physico-chemical properties. This method allows the simultaneous analysis of both cations and anions in a single run, using CE to divide the run into two time segments in normal polarity mode. For this purpose, ESI polarity was switched once during the run, increasing sensitivity and data quality. The method was applied to spiked powdered milk and melamine-contaminated powdered milk, with two sample preparation procedures

Sialic acid linkage differentiation of glycopeptides using capillary electrophoresis - electrospray ionization - mass spectrometry

Proteomic

Development and Psychometric Evaluation of the Demands of Immigration Scale

The Demands of Immigration Scale (DI) measures demands associated with immigration, including loss, novelty, occupational adjustment, language accommodation, discrimination, and not feeling at home in the resettlement country. The DI scale was evaluated in a sample of 1,647 immigrants from the former Soviet Union who had resided in the United States from a few months to 20 years. Confirmatory factor analysis supported the proposed factor model. The DI subscales were internally consistent and had good test-retest reliability. Support for concurrent validity was demonstrated by correlations in the expected direction between the DI total and subscale scores and measures of depression and somatization. Support for discriminant validity was demonstrated by mean group differences in some or all of the DI dimensions according to age and years in the United States

Analysis of hemoglobin-based oxygen carriers by CE-UV/Vis and CE-ESI-TOF/MS.

Blood doping involves the use of products that enhance the uptake, transport, or delivery of oxygen to the blood. One approach uses artificial oxygen carriers, known as hemoglobin-based oxygen carriers (HBOCs). This study describes an analytical strategy based on CE for detecting intact HBOCs in plasma samples collected for doping control. On-capillary detection was performed by UV/Vis at 415 nm, which offered detection selectivity for hemoproteins (such as hemoglobin and HBOCs). On-line ESI-MS detection with a TOF analyzer was further used to provide accurate masses on CE peaks and to confirm the presence of HBOCs. An immunodepletion sample preparation step was mandatory prior to analysis, in order to remove most abundant proteins that interfered with CE separation and altered the ESI process. This analytical method was successfully applied to plasma samples enriched with Oxyglobin, a commercially available HBOC used for veterinary purposes. Detection limits of 0.20 and 0.45 g/dL were achieved in plasma for CE-UV/Vis at 415 nm and CE-ESI-TOF/MS, respectively

Modeling, identification and joint impedance control of the Atlas arms

Compliant manipulation has become central to robots that are sought to safely act in and interact with unstructured as well as only partially known environments. In this paper we equip the hydraulically actuated, position controlled arms of the Atlas robot with model-based joint impedance control, including suitable damping design, and experimentally verify the proposed algorithm. Our approach, which originates from the advances in soft-robotics control, relies on high-performance low-level joint torque control. This makes it independent from the actual technology being hydraulic or electromechanical. This paper describes the approach to accurately model the dynamics, and design the optimal excitation trajectory for system identification to enable the specification of model-based feed-forward controls. In conclusion, the implemented controller enables the robot arm to execute significantly smoother motions, be compliant against external forces, and have similar tracking performance as compared to the existing position control scheme. Finally, unknown modeling inaccuracies and contact forces are accurately estimated by a suitable disturbance observer, which will be used in the future to further enhance our controller’s performance

CE-ESI-TOF/MS for human growth hormone analysis.

CE is a powerful analytical tool used to separate intact biomolecules such as proteins. The coupling of CE with TOF/MS produces a very promising method that can be used to detect and identify proteins in different matrices. This paper describes an efficient, rapid, and simple CE-ESI-TOF/MS procedure for the analysis of endogenous human growth hormone and recombinant human growth hormone without sample preparation. Operational factors were optimized using an experimental design, and the method was successfully applied to distinguish human growth hormone and recombinant human growth hormone in unknown samples