Author


KNAUER Wissenschaftliche Geräte GmbH

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Benefits of UHPLC

This application note shows the performance of the KNAUER AZURA UHPLC system to speed up your method and increase throughput preserving resolution.


Carmen Ziegler

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Improving on AOAC 2001.02: GOS Determination in Foods Using HPAEC–PAD

An improved method for determining total galactooligosaccharide (GOS) content in food and supplements using high performance anion exchange chromatography with pulsed amperometric detection is described.


Zoran Sosic

Latest:

Aggregate and Fragment Analysis in Therapeutic Monoclonal Antibodies Using On-Line Size-Exclusion Chromatography with Native Mass Spectrometry

Size-exclusion chromatography (SEC), with the use of ammonium acetate buffer, can be coupled on-line to electrospray ionization MS for the characterization of size variants of therapeutic monoclonal antibodies (mAbs). A quadrupole time-of-flight (QTOF) MS system was employed, and the MS method was optimized to achieve favorable sensitivity for high-mass detection, while maintaining the structural integrity of the aggregates (or high molecular weight species) and fragments (or low molecular weight species).



William Craig Byrdwell

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Breaking the Rules: Two- and Three-Dimensional Chromatography with Four Dimensions of Mass Spectrometry

Two-dimensional liquid chromatography (2D-LC) allows much greater resolution of peaks than is possible in a classical single dimensional separation. For the next development in separations, we employed 2D-LC in two highly orthogonal dimensions of separation with four mass spectrometers for detection, with parallel detection in each dimension. We have further broken ground by using three dimensions of separation with four mass spectrometers, using two parallel second dimensions.


Sean P. McCann

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Go With the Flow: Thinking About Carrier Gas Flow in GC

Successful GC analysis requires careful control of carrier gas. Here, we explain how to measure and control flow rate, use constant pressure vs. constant flow, and more.


Florian Meischl

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Stability and Recovery Influences of Benzo[a]pyrene, Benzo[a]anthracene, Benzo[b]fluoranthene, and Chrysene during Sample Preparation of Plant Matrices

Quantification of European Union (EU)-priority polycyclic aromatic hydrocarbons (PAHs) in plant matrices is a crucial task. Various methods for enrichment and preconcentration, such as the preloaded-pipette tip solid‑phase extraction (SPE) (1), are available. Nevertheless, analyte recovery as a result of homogenization, sample preparation, and extraction are rarely discussed in the field of phytopharmacy. This study deals with the recovery in dry plant extracts, which are typically used in phytopharmaceuticals and reflect the actual polycyclic aromatic hydrocarbon content in the commercially available end product (2). The aim of this study was to monitor benzo[a]pyrene, benzo[a]anthracene, chrysene, and benzo[b]fluoranthene loss of spiked samples as a result of commonly-used sample pretreatment, extraction, filtering, and evaporating techniques in 1:1 (v/v) cyclohexane–ethyl acetate primulae flos and sambuci flos dry extracts. Results showed that improper sample preparation can lead to false results. In the case of benzo[a]pyrene with a deviation of 155% from the theoretical true value.