Agilent Technologies

About: Agilent Technologies is a company organization based out in Santa Clara, California, United States. It is known for research contribution in the topics: Signal & Mass spectrometry. The organization has 7398 authors who have published 11518 publications receiving 262410 citations. The organization is also known as: Agilent Technologies, Inc..

Photonic crystal microcavity sensor for ultracompact monitoring of reaction kinetics and protein concentration

Abstract: We report on time-resolved label-free monitoring of protein binding in a physiological buffer using a photonic crystal microcavity sensor of total area 50 μm2 with an effective detection area of 0.272 μm2. We use this ultracompact sensor to monitor the binding of anti-biotin to biotinylated-bovine serum albumin (b-BSA), and measure an affinity constant of 6.94 × 107 M−1. We show that this photonic crystal sensor can be used for anti-biotin detection at concentrations ranging from picomolar to micromolar. The lower limit of detection for anti-biotin is less than 20 pM, corresponding to less than 4.5 fg of bound material on the sensor surface and fewer than 80 molecules in the modal volume of the microcavity. The sensor also has the capability of measuring binding of small molecular species such as aromatic rings (98 Da). Furthermore, we show that the active surface of the sensor can be successfully regenerated and re-used in subsequent protein binding experiments. A comparison of experimental and theoretical data is given, and the current experimental limitations of the sensor with regard to noise are discussed.

Analysis of diluted sea-water at the ng L−1 level using an ICP-MS with an octopole reaction cell

Abstract: An ICP-MS with an octopole reaction/collision cell was used for the multi-element determination of trace elements in sea-water. The use of a reaction or collision gas, respectively, reduces serious spectral interferences from matrix elements such as ArCl+ or ArNa+. On introducing He or H2 to the cell, detection limits of 0.3 ng L−1 for U to 20 ng L−1 for Fe and As were determined in 10-fold diluted sea-water. The trace elements V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Pb and U were determined in diluted sea-water samples (certified reference material: NASS-5, SLEW-3) with a trueness of ±20% to the certified values. For most of the elements an accuracy of better than 19% was achieved with no sample pre-treatment other than simple dilution.

Separation of twenty underivatized essential amino acids by capillary zone electrophoresis with contactless conductivity detection.

Abstract: Twenty underivatized essential amino acids were separated using capillary zone electrophoresis and consequently detected with contactless conductivity detection (CCD). A simple acidic background electrolyte (BGE) containing 2.3 M acetic acid and 0.1% w/w hydroxyethylcellulose (HEC) allowed the electrophoretic separation and sensitive detection of all 20 essential amino acids in their underivatized cationic form. The addition of HEC to the BGE suppressed both, electroosmotic flow and analyte adsorption on the capillary surface resulting in an excellent migration time reproducibility and a very good analyte peak symmetry. Additionally, the HEC addition significantly reduced the noise and long-term fluctuations of the CCD baseline. The optimized electrophoretic separation method together with the CCD was proved to be a powerful technique for determination of amino acid profiles in various natural samples, like beer, yeast, urine, saliva, and herb extracts.

Comparing functional and structural tests

Abstract: This paper describes an experimental study to understand issues and requirements for structural-based testing using low cost testers, compared to functional-based testing using expensive testers. Several studies have been directed at the effectiveness of various test methods, but none explicitly addressed issues involved in attempting to replace functional vectors with scan vectors and none carried the experiment further by placing defective chips into systems and running system tests. This paper describes the results of such an experiment and offers insight into necessary requirements for reduction or elimination of functional tests.