Microplate Assembly Kit with Glass Rods for Absorbance
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Solution Overview
Problem
Conventional microplate designs for absorbance measurements face inaccuracies due to variations in optical path length caused by deviations in liquid sample volume and evaporation, especially when handling small sample volumes, which complicates automated and efficient handling and measurement processes.
Innovation Solution
A microplate assembly kit featuring an upper plate with downwardly protruding glass rods and a lower plate with wells, utilizing alignment guides and adjustable spacers to maintain a consistent optical path length, ensuring the liquid sample is securely contained and minimizing evaporation exposure, allowing for precise absorbance measurements regardless of sample volume variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional microplates with open wells are used for absorbance measurements, then the device complexity is reduced and ease of operation is improved, but measurement precision deteriorates due to optical path length variations caused by sample volume deviations and evaporation
Solution Approach 1:
The patent implements a nested structure where a cuvette assembly is placed within each well of the microplate. The cuvette contains the liquid sample and is surrounded by a reflective surface, creating a nested configuration that maintains a fixed optical path length while preserving the simplicity of the overall microplate structure for automated handling.
Solution Approach 2:
The patent introduces a reflective surface as an intermediary element between the light source and the liquid sample. This reflective surface ensures that light travels through the sample along a fixed path regardless of sample volume variations, thereby maintaining measurement precision without requiring complex volume control mechanisms.
2Productivity
If the liquid sample volume is minimized to handle large numbers of samples efficiently, then productivity is improved, but measurement precision deteriorates due to increased evaporation and optical path length deviations
Solution Approach 1:
The cuvette assembly nested within each well provides a contained environment for the liquid sample. This nested structure protects the sample from evaporation while maintaining minimal volume requirements, enabling efficient handling of large numbers of samples without compromising measurement precision.
Solution Approach 2:
The reflective surface acts as an intermediary that compensates for optical path length variations caused by minimal sample volumes. By ensuring light travels through the sample along a fixed path defined by the cuvette and reflective surface geometry, the system maintains measurement accuracy even with minimized sample volumes.
3Measurement precision
If flat surfaces are used to hold the liquid sample as disclosed in US 8,605,279 B2, then the device complexity is reduced, but measurement precision deteriorates due to sensitivity to mechanical influences and evaporation
Solution Approach 1:
The patent nests a cuvette assembly within each well, creating a contained structure that holds the liquid sample. This nested configuration provides a fixed optical path length through the sample while protecting it from mechanical influences and evaporation, achieving measurement precision without requiring complex external holding mechanisms.
Solution Approach 2:
The reflective surface serves as an intermediary element that defines a fixed optical path through the liquid sample. This intermediary structure ensures consistent optical path length regardless of sample volume or mechanical disturbances, maintaining measurement precision while using a relatively simple cuvette assembly design.
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 kit enables accurate and efficient absorbance measurements by maintaining a fixed optical path length and reducing evaporation effects, accommodating variations in sample volume while ensuring the liquid sample remains contained during handling and measurement, thus improving measurement accuracy and reliability.
Implementation Method 1
the concentration of a single attenuating component in the liquid sample can be determined in case the optical path length is precisely known by the linear relationship between the absorbance and the concentration from the equation: A = ε·L·c
Implementation Method 2
the flat rod bottom surfaces of all rods of a same individual plurality of rods are arranged in a respective common first plane... the flat well bottom surfaces of all wells are arranged in a common second plane... one end of the respective threaded adjustment bolt abuts against the lower plate or the upper plate, respectively, such that when the upper plate is assembled with the lower plate to form the microplate assembly, the flat rod bottom surface of each rod of each individual plurality of rods is arranged parallel to the corresponding flat well bottom surface and faces the flat well bottom surface at a predetermined distance
Implementation Method 3
the formation of a meniscus may lead to a non-uniform optical path length across the liquid-air interface and a significant deviation from the theoretically assumed optical path length
Implementation Method 4
deviations of the actual volume of the liquid sample from the desired volume of the liquid sample caused by inaccurate pipetting or by evaporation of the liquid sample during the time between pipetting the sample into the wells and performing the measurements
Data Source
AI summary
A kit for forming a microplate assembly for absorbance measurements of liquid samples comprises an upper plate (1) comprising at least one plurality of rods (12), each rod (12) having a flat rod bottom surface (121), a lower plate (2), and alignment guides for aligning the upper plate (1) and the lower plate (2) relative to each other as well as spacers for determining the distance of the upper plate (1) and the lower plate (2) relative to each other. The lower plate (2) comprises a plurality of wells (22), each having a flat well bottom surface (221). The alignment guides are configured and arranged such that each well (22) accommodates one rod (12) of each plurality of rods. The spacers comprise a plurality of threaded adjustment bolts (13a, 13b, 13c) which are arranged such that, when the upper plate (1) and the lower plate (2) are assembled to form the microplate assembly, each flat rod bottom surface (121) is arranged parallel to the corresponding flat well bottom surface (221) at a predetermined distance (43) in the range of 0.5 mm to 5 mm.