Agilent Manuals

A variety of heat-shock proteins (HSPs) were identified in E. coli grown under heat-shock conditions using Agilent Nanoflow Proteomics Solution.

This Application Note demonstrates the Agilent Nanoflow Proteomics Solution system1) as a powerful tool for analysis of proteomics samples. Using the approach of cation exchange, sample enrichment, reversed phase chromatography and nanospray ion trap mass spectrometry with subsequent database search, all of ten proteins were identified from a tryptic digestion model mixture and hundreds of proteins from a complex E. coli cell lysate.

This Application Note describes a method for increasing the resolution of complex proteome samples by using two-dimensional offline LC/MS. The method applies a continuous salt gradient in the first separation dimension, which can significantly increase the number of identified proteins from complex samples due to higher chromatographic resolution compared to stepwise elution. In addition, the method offers high flexibility for the investigator since micro fractions of the first dimension can be stored, re-analyzed or chemically modified prior to further analysis. To achieve optimal resolution, the applied 2D LC method strongly requires optimization of the two separation dimensions. Especially elution gradients, analysis time, stationary phase material, and column dimension need to be designed and assembled adequately to attain a considerable increase in overall peak capacity. This Application Note shows data which influences the variables and components. It can serve as a guideline for the investigator to adapt his separation method for a specific proteome sample in order to achieve maximum peptide sequence information by MS/MS analysis. This will result in a maximum of identified proteins after a database search.

Off-line multidimensional LC/MS can provide high resolution mass spectra, and improve protein identification

This application note describes a method to separate organic acids by ion suppression chromatography (ISC) using reversed-phase liquid chromatography columns and diode array detection. Experiments were performed using a new ZORBAX SB Aq column that successfully separated organic acids. Two standard mixtures of organic acids and a number of soft drinks and wines were analyzed.

This article discusses the application of mass spectrometry technology in protein research, focusing on the advantages and challenges of electrospray ionization combined with time-of-flight mass spectrometer for protein identification.

The paper introduces the application of LC/MS in drug monitoring, which can be used to analyze over 200 drugs, including identification and quantification.

Mass-based fraction collection of compound libraries using the Agilent 1100 Series purification system

This Application Note describes the optimization of the Agilent 1100 Series high throughput LC/MS system for different analytical tasks. It provides detailed instructions on how to optimize chromatography, diode-array and MSD detection to achieve highest sample throughput in combination with substance identification, how to acquire quantitative information while maintaining very high sample throughput, and how to achieve fast analysis of very low sample amounts.

This document describes a routine method for the quantitative determination of 4-nonylphenol (NP), 4-nonylphenol monoethoxylate (NP1EO), and 4-nonylphenol diethoxylate (NP2EO) in sludge samples. A Soxtec® extraction procedure was used to enrich the target compounds from the solid matrix. Quantitative determinations were performed by high-speed gas chromatography/mass spectrometry using a short apolar fused silica column. Derivatization allows NP1EO and NP2EO to be analyzed by gas chromatography. The relative standard deviation was close to 5% for the analysis of 10 different sludges analyzed seven times each. Recoveries were determined for a sludge reference material and were higher than 90%. The experimental limits of quantification were 2, 5, and 5 µg/g of dry matter (µg/g DM), respectively, for NP, NP1EO, and NP2EO. Good agreement was observed between results obtained with this method and those obtained by our previous method, which used normal-phase liquid chromatography with an aminosilica column. This method was applied to the determination of alkylphenols and alkylphenol mono- and diethoxylates in sewage sludge by high-speed gas chromatography/mass spectrometry.

This paper presents a method for determining sub-ppb levels of perchlorate anion using ion chromatography/mass spectrometry (IC/MS). The IC/MS method follows EPA Method 314 methodology originally developed for IC with conductivity detection at the single ppb range [1]. The IC/MS method is not affected by the addition of the interference matrix described in Method 314 on perchlorate recoveries throughout the measurable range. Typical recoveries are 90%–105% at the 0.5 and 1-ppb level in synthetic drinking and waste waters with the method detection limit (MDL) less than 100 ppt.

The U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) has established a database entry for Bacillus anthracis using the Sherlock® Microbial Identification System (MIS) from MIDI, Inc. The Sherlock MIS identifies over 1,500 species of bacteria, including six bacteria considered potential agents of biological terrorism, through gas chromatographic analysis of fatty acid methyl esters (FAMEs). The new B. anthracis data set entry in the Sherlock Bioterrorism Library allows for accurate identification of B. anthracis isolates, estimation of strain relatedness, and potential forensic analysis for attribution of biological threat agent use.