Electrospray Apparatus for Uniform Polymer Specimen Deposition
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Solution Overview
Problem
MALDI mass spectrometry lacks reproducibility for quantitative analysis of polymers, particularly due to variations in specimen thickness affecting ionization efficiency and pattern consistency, and existing techniques are not applicable to commercialized MALDI-TOF MS equipment.
Innovation Solution
A method using an electrospray apparatus with a main nozzle and auxiliary nozzle, along with a mask to control specimen thickness and a sheath gas for precise deposition on a sample plate, ensuring a thickness deviation of 30% or less, allowing for uniform specimen preparation suitable for commercial MALDI-TOF equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrospray method is used for specimen preparation, then the specimen can be deposited on sample plate, but the specimen thickness varies significantly leading to poor reproducibility of MALDI spectrum
Solution Approach 1:
A mask with a hole of specific diameter (0.5-2.0 mm) is introduced as an intermediary component between the electrospray nozzle and sample plate. This mask mediates the deposition process by restricting the spray area to the center region, thereby controlling specimen thickness uniformity and improving MALDI spectrum reproducibility
Solution Approach 2:
The invention applies local quality by selecting only the center region of the electrospray jet for specimen deposition. The mask with a central hole restricts the spray to the core area where the most uniform and controlled polymer sample is deposited, excluding the periphery where thickness variation is greater
2Reliability
If matrix is sprayed along with polymer sample from main nozzle, then ionization can occur, but matrix deposits in vicinity of nozzle causing clogging and reduced reliability
Solution Approach 1:
The invention segments the electrospray system into two independent nozzles: a main nozzle for polymer sample delivery and an auxiliary nozzle for matrix delivery. This segmentation allows separate control of sample and matrix deposition, preventing matrix clogging of the main nozzle while ensuring consistent ionization
Solution Approach 2:
The auxiliary nozzle acts as an intermediary that delivers matrix to the specimen after the polymer sample has been deposited by the main nozzle. This intermediate step ensures matrix is present for ionization without causing clogging in the primary sample delivery path
3Measurement precision
If quantitative analysis is performed on polymer using conventional MALDI, then molecular weight information can be obtained, but the results lack reproducibility across different specimens and analysis spots
Solution Approach 1:
The invention changes the specimen preparation parameters by controlling deposition area through the mask hole diameter (0.5-2.0 mm) and selecting the center region of the electrospray jet. These parameter changes result in specimens with thickness deviation of 30% or less, enabling reproducible quantitative analysis across different specimens and analysis spots
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
The method achieves reproducible MALDI spectra with a relative standard deviation of 30% or less, enabling efficient and quick quantitative analysis of polymers across multiple specimens and analysis spots.
Implementation Method 1
a main nozzle (110) for electrospray of a polymer sample which is a mixed solution of a polymer compound, a matrix and a solvent
Implementation Method 2
spraying the solvent from an auxiliary nozzle (120) surrounding the main nozzle (110) and coaxial with the main nozzle (110), so as to prevent the matrix from being deposited in the vicinity of the main nozzle (110)
Implementation Method 3
jetting a sheath gas through a sheath gas supply pipe (130) so that the sheath gas guides the polymer sample to be sprayed onto the predetermined position of the sample plate
Data Source
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AI summary
The present invention provides a method enabling a quantitative analysis of a polymer by MALDI mass spectrometry, and a method for manufacturing a sample for MALDI mass spectrometry for a quantitative analysis of a polymer. To that end, the methods can increase reproducibility of a MALDI spectrum by making uniform the thickness of a sample affecting the pattern in a polymer MALDI spectrum. The sample according to the present invention is applicable also to a commercial MALDI-TOF instrument, and, thus, can quantitatively analyze a polymer in a more efficient and faster manner.