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Non-Visual Delivery of Accurate Volumes to Improve Laboratory Access for Blind Students


Charis Glatthar

Metropolitan State University of Denver


In the analytical chemistry laboratory, volumetric glassware is used to transfer accurate and precise quantities of liquids for analysis. These devices require the analyst to visually align the level of liquid with a fill line printed on the glassware. For blind chemists, this is not possible, which creates a barrier for their participation in this field. As an alternative, we investigated the amount of error between tacked syringes and notched syringes as a method for measuring liquid chemicals for blind and low-vision (BLV) students to determine which are better suited for analytical laboratory work. Seven syringes of differing brands and/or volumetric quantities were marked with tactile indicators, either a notch cut into the fin of the plunger or a tack pushed into the syringe to physically stop the plunger. These were calibrated with deionized water and their accuracy and precision were compared to the tolerance of class A volumetric pipettes. Variation between individuals was analyzed using a group of 10 volunteers measuring trials from a notched and tacked syringe while wearing sleep shades, and the results were compared using ANOVA and compared to syringe calibration data. Once we determined the tacked syringe was more precise and accurate, we used a common analytical procedure, the spectrophotometric analysis of iron, to compare the accuracy and precision obtained by a blind student using the tacked syringe to that obtained with the standard method using volumetric glassware, which was carried out by sighted analytical chemistry laboratory students.