What are the modes of triple quadrupole scan?

The Triple Quadrupole Mass Spectrometer (Triple Quadrupole MS) enables various analytical modes by effectively combining two quadrupole mass analyzers and a collision cell. The analytical modes include six types: scan, SIM (Selected Ion Monitoring), product ion scan, precursor ion scan, neutral loss scan, and MRM (Multiple Reaction Monitoring, also known as SRM). While scan and SIM are also possible with Single Quadrupole Mass Spectrometer, the other analytical modes are unique to Triple Quadrupole LC-MS. Among these modes, MRM is the most commonly used, as it allows for highly selective and sensitive quantification of trace components in complex samples such as biological or food samples containing numerous impurities. Product ion scan, precursor ion scan, and neutral loss scan are effective analytical modes for obtaining structural information about molecules, enabling qualitative examination of functional groups, molecular skeletons, and ion clusters that share common characteristics.

Triple Quadrupole LC-MS/MS

Q: What is triple quadrupole LC-MS?

Triple quadrupole LC-MS is an integrated system that combines a Liquid Chromatograph (LC) with a triple quadrupole mass spectrometer. In a triple quadrupole mass spectrometer, two quadrupole mass analyzers are arranged in series, with a quadrupole (or other multipole) that does not perform m/z separation placed between them as a collision cell. The first quadrupole mass analyzer selects precursor ions, which are then fragmented in the collision cell. During the fragmentation process, Collision-Induced Dissociation (CID), utilizing collisions with argon or nitrogen gas, is employed. The resulting product ions are subsequently analyzed for their mass in the second quadrupole mass analyzer.

Q: What is the difference between single quadrupole MS, tandem MS and triple quadrupole?

Structurally, the Single Quadrupole Mass Spectrometer (Single Quadrupole MS) has only one quadrupole mass analyzer, whereas the Triple Quadrupole Mass Spectrometer (Triple Quadrupole MS) consists of two quadrupole mass analyzers with a collision cell placed between them. In the Single Quadrupole MS, mass analysis (MS) is performed only once, but in the Triple Quadrupole MS, two stages of mass analysis (MS/MS) are possible. Consequently, the Triple Quadrupole MS offers higher selectivity compared to the Single Quadrupole MS, making it highly useful for analyzing complex samples such as biological or food samples containing numerous impurities. Additionally, MS/MS significantly reduces noise, enabling a higher signal-to-noise (S/N) ratio, which facilitates highly sensitive analysis of trace components.

A triple quadrupole mass spectrometer (LC-MS/MS) is an incredibly powerful tool used in analytical chemistry. The LC-MS/MS is becoming increasingly common in cutting-edge laboratories due to its high sensitivity, specificity and quantitative accuracy when detecting even small amounts of components in sample materials. For this reason, the LC-MS/MS instruments are frequently used in many industries and applications, including environmental testing, clinical research, and forensic examination. The Shimadzu LC-MS/MS systems, including the LCMS-TQ RX series and LCMS-8065XE, are renowned for their speed of analysis, robustness and data reliability.

How it works

Mass spectrometers consist of three main components: the ionization unit, the mass separation unit, and the ion detection unit. These units process samples that have previously been separated and delivered by LC. The mass separation and detection processes take place in a high-vacuum environment.

In the ionization unit, the introduced components are efficiently ionized. These ionized components are separated in the mass separation unit based on differences in their m/z values. When ions reach the ion detection unit, they are converted into electrical signals, which are output as data for analysis.

The sample solution delivered from the LC is sprayed together with nitrogen gas in the ionization unit, generating ions. The liquid chromatography-mass spectrometry is characterized by performing ionization under atmospheric pressure (atmospheric pressure ionization, API), where the solvent is removed in the atmosphere. Currently, two widely used ionization methods are electrospray ionization (ESI), which generates ions from the liquid phase, and atmospheric pressure chemical ionization (APCI), which generates ions from the gas phase.

The single quadrupole mass spectrometer (LC-MS) has one quadrupole responsible for mass separation, whereas the LC-MS/MS consists of two quadrupoles for mass separation and a collision cell in between for fragmenting ions. These three stages are referred to as Q1 (the first quadrupole), Q2 (the collision cell), and Q3 (the second quadrupole), and this configuration is what defines the "triple quadrupole mass spectrometer." This setup allows the LC-MS/MS to obtain more information compared to the LC-MS, which has only one quadrupole.

The most commonly used measurement mode in the LC-MS/MS is multiple reaction monitoring (MRM, also referred to as selected reaction monitoring, SRM), which enables highly sensitive quantification—a key feature of the LC-MS/MS. In this mode, Q1 is set to allow only ions with a specific m/z value to oscillate stably, passing only the selected precursor ions while excluding others. Next, in the collision cell, the precursor ions collide with inert gas, causing fragmentation through collision-induced dissociation (CID). The resulting fragment ions, referred to as product ions, are then selectively allowed to pass through Q3, where they are detected by the detector and converted into electrical signals for analysis.

Although the number of ions reaching the detector decreases, unwanted ions are excluded, resulting in high selectivity. This makes the method highly effective for the sensitive quantification of samples containing multiple components. In the quantification process of the LC-MS/MS, ions generated in the collision cell are measured by the second quadrupole, enabling detection with even higher selectivity.

By combining Shimadzu's Nexera series ultrafast liquid chromatographs with the LCMS-8000 series capable of ultrafast mass spectrometry (UFMS), it is possible to acquire a large amount of data in a short time. When analyzing both positive and negative ions simultaneously in a single analysis, switching between positive and negative ion modes is required. Shimadzu's LC-MS/MS boasts an ultrafast ploarity switching time of 5 milliseconds (UFswitching). This feature enables excellent quantification results even in cases where signal peaks from components with different polarities appear within just a few seconds.
UF Technology (Learn more)

Additionally, the system incorporates advanced technologies such as ultrafast scanning and a collision cell designed for efficient ion transport, enabling simple and rapid multi-component simultaneous analysis with high sensitivity and speed. Alongside these high-speed capabilities, the system includes the "PERFORMANCE CONCIERGE" feature for self-diagnosis of system status, ensuring robust and stable analysis. Shimadzu's LC-MS/MS delivers high reliability and performance for a wide range of applications.

Applications

LC-MS/MS is equipped with high sensitivity and selectivity, making it suitable for use in a range of applications, particularly those involving quantitative analysis.

In pharmaceutical analysis, it has become an essential tool at every stage of drug development, including drug discovery, clinical research, and quality control. It is utilized in pharmacokinetic studies, quantification of trace pharmaceuticals, biomarker quantification, and metabolic analysis.

In the food and beverage industry, it plays a crucial role in safety assessments, quality control, and regulatory compliance. It is used for the detection and analysis of pesticide residues, veterinary drugs, and food additives, as well as for the evaluation of nutritional components and functional ingredients.

In the environmental field, it is employed to analyze pollutants and chemicals such as PFAS in complex matrices like water, soil, and air with high sensitivity.

In forensic science and clinical research, it is used for drug screening and quantification, as well as for the exploration and quantification of biomarkers.

The LC-MS/MS from Shimadzu is widely used across these fields due to its high sensitivity, selectivity, and excellent performance, especially considering its cost. It is particularly characterized by its suitability for high-speed analysis and is highly regarded in applications such as pesticide analysis, environmental analysis, and metabolite analysis, where simultaneous multi-component analysis is required.

FAQs

What is Triple Quadrupole Mass Spectrometer (LC-MS/MS)?

Triple quadrupole mass spectrometer (LC-MS/MS) is an integrated system that combines a liquid chromatograph (LC) with a triple quadrupole mass spectrometer. In a triple quadrupole mass spectrometer, two quadrupole mass analyzers are arranged in series, with a quadrupole (or other multipole) that does not perform m/z separation placed between them as a collision cell. The first quadrupole mass analyzer selects precursor ions, which are then fragmented in the collision cell. During the fragmentation process, CID, utilizing collisions with argon or nitrogen gas, is employed. The resulting product ions are subsequently analyzed for their mass in the second quadrupole mass analyzer.

What is the difference between a single quadrupole mass spectrometer (LC-MS) and a triple quadrupole mass spectrometer (LC-MS/MS)?

Structurally, the single quadrupole mass spectrometer (LC-MS) has only one quadrupole mass analyzer, whereas the triple quadrupole mass spectrometer (LC-MS/MS) consists of two quadrupole mass analyzers with a collision cell placed between them. In the single quadrupole mass spectrometer (LC-MS), mass analysis (MS) is performed only once, but in the triple quadrupole mass spectrometer (LC-MS/MS), two stages of mass analysis (MS/MS) are possible. Consequently, the triple quadrupole mass spectrometer (LC-MS/MS) offers higher selectivity compared to the single quadrupole mass spectrometer, making it highly useful for analyzing complex samples such as biological or food samples containing numerous impurities. Additionally, MS/MS significantly reduces noise, enabling a higher signal-to-noise (S/N) ratio, which facilitates highly sensitive analysis of trace components.

What are the modes of a triple quadrupole mass spectrometer (LC-MS/MS)?

The triple quadrupole mass spectrometer (LC-MS/MS) enables various analytical modes by effectively combining two quadrupole mass analyzers and a collision cell. The analytical modes include six types: scan, SIM, product ion scan, precursor ion scan, neutral loss scan, and MRM. While scan and SIM are also possible with single quadrupole mass spectrometer (LC-MS), the other analytical modes are unique to triple quadrupole mass spectrometer (LC-MS/MS). Among these modes, MRM is the most commonly used, as it allows for highly selective and sensitive quantification of trace components in complex samples such as biological or food samples containing numerous impurities. Product ion scan, precursor ion scan, and neutral loss scan are effective analytical modes for obtaining structural information about molecules, enabling qualitative examination of functional groups, molecular skeletons, and ion clusters that share common characteristics.

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