A brief introduction is presented to the basic principles and application of a quadrupole-time-of-flight (TOF) tandem mass spectrometer. The main features of reflecting TOF instruments with orthogonal injection of ions are discussed. Their operation and performance are compared with those of triple quadrupoles with electrospray ionization and matrix-assisted laser desorption/ionization (MALDI) ...

Figure 1 Classification of chromatograms are based on the relative abundance of all the peaks in the mixture. Chromatography is an extremely versatile technique for the analytical laboratory. The chromatographic patterns generated by modern instruments are used in a wide variety of quantitative and qualitative analyses. The techniques are robust enough (and we have assembled experience enough) ...

Gas chromatography/mass spectrometry (GC/MS) with negative ion chemical ionization permits detection of underivatized patulin in apple juice extracts while minimizing co-extractive responses. The technique has been used with a variety of capillary columns in quadrupole, ion trap, and magnetic sector GC/MS instruments to confirm presumptive findings of patulin in apple juice at concentrations ra...

This paper presents a miniature wrist that can be integrated into needle-sized surgical instruments. The wrist consists of a nitinol tube with asymmetric cutouts that is actuated by a single tendon to provide high distal curvature. We derive and experimentally validate kinematic and static models for the wrist and describe several prototype wrists, illustrating the straightforward fabrication a...

Metabolic profiling is routinely performed on multiple analytical platforms to increase the coverage of detected metabolites, and it is often necessary to distribute biological and clinical samples from a study between instruments of the same type to share the workload between different laboratories. The ability to combine metabolomics data arising from different sources is therefore of great i...

The existence of pharmaceuticals and illicit drugs (PIDs) in environmental waters has led many analytical chemists to develop screening methods for monitoring purposes. Water samples can contain a huge number of possible contaminants, commonly at low concentrations, which makes their detection and identification problematic. Liquid chromatography coupled with high resolution mass spectrometry (...

results under the above chromatography condition, biuret compound (peqb) and the internal standard were detected at 4.5 and 13.5 minutes, respectively. limit of quantitation of the peqb was 0.1 µg/ml. accuracy of the method over the concentration range of 0.1-100 µg/ml was between 88-109%. inter- and intraday precisions were 4-19% and 6-8%, respectively. a good relationship in the form of a pow...

Increasing importance of pharmaceutical plants in the world and the presence of many of these plants in our country, which has one of the richest Flora of the world, suggest the need for comprehensive studies. Research of secondary metabolites of medicinal and essential oily plants from Iran’s dry to super dry deserts is very important. One of the most famous species from “Labiatae” family is D...