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Kevin J. McHale, Ph.D. & Dipankar Ghosh, Ph.D., Thermo Fisher Scientific
The TSQ Quantum product line is the most sensitive series of triple quadrupole mass spectrometers available in the market today, capable of consistently producing linear dynamic ranges for quantitative assays.
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This can be ascribed partially to the highly efficient conversion dynode/electron multiplier used on all TSQ Quantums (Figure 1).
The off-axis design prevents the neutrals from striking the detector, thereby decreasing background noise. Each ion passing from Q3 collides with the conversion dynode to produce many secondary particles, creating an amplification effect. Further amplification is achieved when the secondary particles strike the electron multiplier.
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| [Click to Enlarge Fig.1] |
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| The dynode/multiplier detection system on the TSQ Quantum platform not only leads to the highest sensitivity, but also to the widest linear dynamic range of any triple quadrupole system on the market. Figures 2-6 show representative data illustrating linear dynamic ranges of 4-6 orders of magnitude on the TSQ Quantum.
The calibration curve in Figure 2 demonstrates that the TSQ Quantum not only has great sensitivity (LOQ 1 fg), but also an incredible linear dynamic range of six orders of magnitude. |
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[Click to Enlarge Fig.2] |
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Figures 3 and 4 show additional examples of the wide linear dynamic range of the TSQ Quantum. Inspection of the area responses of the drug loperamide at 10 pg/mL and 100,000 pg/mL (Figure 3) shows a linear, not quadratic, increase in the area with sample concentration. |
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| [Click to Enlarge Fig.3] |
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[Click to Enlarge Fig.4] |
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Figure 5 presents representative chromatograms for 1-hydroxymidazolam at the lower and upper limits of quantitation. Again, a linear area response is observed on the TSQ Quantum for a concentration range of over 4 orders of magnitude (0.025 – 1000 ng/mL). The corresponding calibration curve for 1-hydroxymidazolam with a linear regression fit (R2 = 0.9999) is shown in Figure 6.
The superior design of the TSQ Quantum’s detection system simplifies the process of achieving lower detection limits and quantitating compounds over several orders of magnitude.
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| [Click to Enlarge Fig.5] |
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[Click to Enlarge Fig.6] |
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