ICP-MS P/A Coefficient Calibration via Ion Lens Voltage Adjustment
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Solution Overview
Problem
Current inductively coupled plasma mass spectroscopy (ICP-MS) methods for determining the pulse-to-analog (P/A) coefficient are labor-intensive, require multiple sample preparations, and often result in inaccurate estimations due to linear interpolation based solely on mass number, leading to increased errors.
Innovation Solution
An ICP-MS apparatus and method that uses standard density samples to generate a working curve and adjusts ion lens voltage to ensure signal intensities fall within a calibration range, combined with a P/A coefficient estimation method that correlates P/A coefficients from different measurements to accurately determine coefficients for mass numbers outside the initial calibration range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sample preparations are performed for P/A coefficient calibration for each element, then the P/A coefficient can be determined accurately, but the measurement process becomes labor-intensive and time-consuming
Solution Approach 1:
The patent applies universality by using a single multi-element standard sample that can determine P/A coefficients for multiple elements simultaneously, rather than preparing separate single-element samples for each element. This multi-functional standard sample enables concurrent calibration across the entire measurement range, dramatically reducing preparation time and labor while maintaining calibration accuracy.
Solution Approach 2:
The patent implements preliminary action by preparing a comprehensive multi-element standard sample in advance that covers the entire dynamic range. This pre-prepared standard contains multiple elements at various concentrations, allowing all necessary P/A coefficient calibrations to be performed in a single measurement session rather than requiring separate preparations for each element.
2Adaptability or versatility
If linear interpolation is used to estimate P/A coefficients for mass numbers outside calibration range, then estimation can be performed, but the accuracy decreases due to increased errors
Solution Approach 1:
The patent applies parameter changes by expanding the calibration range to cover the entire measurement dynamic range through optimized standard sample preparation and ion lens voltage adjustment. By ensuring that calibration signals span from the lowest to highest measurement signals, the system eliminates the need for interpolation and allows direct determination of P/A coefficients even for mass numbers at the extremes of the measurement range.
Solution Approach 2:
The patent implements dynamics by adjusting the ion lens voltage dynamically to optimize signal intensities for different mass numbers. The system varies the ion lens voltage to ensure that signals for all elements of interest fall within the calibration range, adapting the measurement conditions to match the calibration parameters for accurate P/A coefficient determination.
3Adaptability or versatility
If ion lens voltage is changed step by step to determine measured values over wide range, then all elements can be measured in calibration range, but measurement time increases significantly
Solution Approach 1:
The patent applies self-service by implementing an automated feedback control system that monitors signal intensities and automatically adjusts ion lens voltage to optimize measurements. The system independently determines the appropriate voltage settings based on real-time signal feedback, eliminating the need for manual step-by-step voltage changes and significantly reducing measurement time while ensuring all elements are measured within the calibration range.
4Difficulty of detecting and measuring
If special hardware such as comparator is added to discriminate signal regions, then signal region discrimination can be performed, but device complexity increases
Solution Approach 1:
The patent applies mechanics substitution by replacing hardware-based signal region discrimination (such as comparators) with software-based processing. The system uses computational algorithms to automatically determine which measurement method (pulse count or analog current) is appropriate for each signal intensity level, eliminating the need for additional hardware components while maintaining accurate signal region discrimination.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces labor and measurement time, enhances accuracy by ensuring all signal intensities are within the calibration range, and allows for precise estimation of P/A coefficients, minimizing errors associated with linear interpolation.
Implementation Method 1
a means for adjusting a voltage applied to the ion lens 30 in accordance with a measured signal intensity to thereby adjust an ion transmission ratio of the ion lens 30
Implementation Method 2
a means for measuring a signal intensity of the ions in two different measurement ranges with two different measurement methods
Implementation Method 3
Inductively coupled plasma mass spectroscopy (ICP-MS) apparatuses
Data Source
AI summary
A method of determining a coefficient for converting an analog current value into a pulse count value in an inductively coupled plasma mass spectroscopy apparatus (ICP-MS) is described. The ICP-MS is configured to generate the pulse count value and the analog current value as a signal intensity indicating a density of an element in a sample to be measured.