Abstract:
A system and related method for improved liquid delivery evaluation uses a solution containing one or more dyes such that the solution exhibits multiple distinct detectable light absorbance spectral features for calibrating or testing over extended volume or dilution ranges. The system includes: a photometric instrument capable of measuring optical absorbance at multiple wavelengths; a sample solution to be dispensed using the liquid delivery system whose performance is being tested or calibrated; and vessels with diluent solution. The sample solutions contain a dye, chosen so that multiple distinct detectable light absorbance spectral features can be distinguished for volume or dilution ranges of interest. The concentrations of the dyes may be chosen so that a large volume delivery device, and a small volume delivery device, are calibrated with the same sample solution but using a different spectral feature with a high absorbance per unit pathlength.
Abstract:
The invention provides ways to determine the impact of diluting a solution wherein the diluting may be carried out for any of a variety of purposes. In one embodiment, the method enables accurate volume dispensation calculations independent of meniscus shape. In another embodiment, the method enables accurate determination of plate washing efficiency. In yet another embodiment, the method enables the accurate determination of dilution ratio over a plurality of dilution steps. The methods described may be carried out using one or more systems arranged to perform the steps. A kit of the invention includes instructions for carrying out the steps of the methods and, optionally, one or more solutions suitable for conducting photometric measurements.
Abstract:
A method for precisely and accurately determining the volume of a test liquid aliquot which can be used to calibrate a liquid delivery device. The method is particularly useful for determining the volume of an aliquot of a test liquid which is complex or non-aqueous, or is both complex and non-aqueous. The test-stock mixture contains at least the test liquid and a stock solution including a first dye, the first dye having absorbance characteristics which are measurably distinguishable from the absorbance characteristics of a second dye. The test-stock mixture is mixed with a diluent including the second dye to form a sample solution to be used to measure absorbances of the first dye and the second dye. The volume of the test-stock mixture aliquot is calculated by using a formula based on the Beer-Lambert law which incorporates the measured absorbance values and a dilution characteristic of the test-stock mixture. The test liquid and the stock solution are combined gravimetrically in a controlled ratio so that the flow characteristics of the test-stock mixture correspond to the flow characteristics of the test liquid and without affecting the ability to distinguish the absorbance characteristics between the first dye and the second dye.