Q-TOF technology

With this in mind, an efficient and rapid approach would be to use the combination of UPLC and Q-TOF technology. The idea behind this approach is to have better ways to filter unwanted false positives with minimal repeat of injections. 

The LCQ and LCQ DECA are products of Thermo Electron Corporation (San Jose, CA) the Q-TOF is a product of Waters (Beverly, MA) the QSTAR, ProQUANT, and ProICAT are products of Applied Biosystems (Foster City, CA) and Spectrum Mill and the MSD TRAP XCT are products of Agilent Technologies (Palo Alto, CA). 

Fig. 4.56. Schematic of the Q-TOF Ultima with ESI ion source in MS/MS mode. The TOF analyzer has a double reflector for higher resolution. Courtesy of Waters Corporation, MS Technologies, Manchester, UK.

ToF analyzers as well as hybrid instruments that combine two or more mass-resolving components, such as quadrupole-ToF (Q-ToF), ion-mobility ToF, and ion-trap-ToF, as well as the high-resolving Fourier transform (FT) analyzer Orbitrap and ion cyclotron resonance (ICR). For targeted analysis, a multiple-reaction monitoring instrument based on triple-quadrupole technologies (QQQ) has provided unrivaled sensitivity for MSI of pharmaceuticals, yet its targeted nature renders it unsuitable for discovery-based research. 

Of the three ionization technologies, MALDI-Q-TOF is arguably the most sensitive and useful type instrument for complex carbohydrate analysis (148). 

In conclusion, UHPLC-MS has a wide range of applications in the determination of polyphenolic compounds in foods. Highly sensitive chromatographic method coupled with mass spectrometry allows the detection and identification of anthocyanins in wine samples (57). Yet another example is the use of the technology to detect polyphenolic compounds. Q-TOF-MS is an excellent tool for the detection and identification of new polyphenols in food. An appropriate selection of chromatographic parameters allows for the quick detection of a large number of polyphenols, including both those with hydrophilic properties as well as hydrophobic properties. The use of small particle size and small diameter of the column represents a major advance for the selectivity, sensitivity, and speed of analysis of polyphenolic compounds in foods. Table 7.2 summarizes the developed UHPLC methods, which were used for the determination of polyphenolic compounds in foods. 

The sample inlet is constituted of a heated fused silica capillary, which is maintained at approximately 200 "C and is encased in a flexible tube. The ion source, in the case of electronic ionization, is composed of electrically heated metallic filaments. Mass analyzers, separating the analytes, include time-of-flight (TOF), linear quadmpole (Q), linear quadrupole ion trap (LIT), quadmpole ion trap (QIT), Fourier transform ion cyclotron resonance (FT-ICR), etc. These detectors differ in their capacity to treat ion beams in a continuous or pulsed (TOF). Quadmpole mass analyzers stabilize and destabilize the ion paths with an oscillating electrical field. A triple quad is more recent technology and consists of three quadmpole stages. Quadmpole ion traps will sequentially eject ions that have been trapped in a ring electrode between two endcap electrodes. 

It can be concluded that applications of UHPLC techniques has been increasing each year. Impressive technological advances in the UHPLC have made it possible to simultaneously determinate many polyphenolic compounds. UHPLC provides high speed and high sensitivity and consumes less mobile phase. Moreover, the combination of ultrahigh pressure liquid chromatography with mass spectrometry greatly increases the sensitivity and selectivity of the quantitative analysis of polyphenolic compounds in complex matrixes. UHPLC-Q-TOE/MS and TOF/MS techniques enable the identification of new polyphenolic compounds in plants. 

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