Abstract: Broad volumetric range pipettes with multi-tiered pipette tip holder and ejection assemblies and methods of using such pipettes are disclosed herein. These pipettes typically include a concentric cylinder arrangement with each outer cylinder configured for contacting and dislodging a pipette tip attached to the tip holder portion of the immediately adjacent inner cylinder. In this manner, different sized pipette tips can be used on a single device. In addition, a locking mechanism is described for locking the large tip holder into a downward position to minimize the extension of the small tip holder and thereby enabling attachment of large, filtered pipette tips and reducing/eliminating the risk that the liquid being transferred will contaminate the pipetting device.

Abstract: Broad volumetric range pipettes with multi-tiered pipette tip holder and ejection assemblies and methods of using such pipettes are disclosed herein. These pipettes typically include a concentric cylinder arrangement with each outer cylinder configured for contacting and dislodging a pipette tip attached to the tip holder portion of the immediately adjacent inner cylinder. In this manner, different sized pipette tips can be used on a single device. In addition, a locking mechanism is described for locking the large tip holder into a downward position to minimize the extension of the small tip holder and thereby enabling attachment of large, filtered pipette tips and reducing/eliminating the risk that the liquid being transferred will contaminate the pipetting device.

Abstract: An improved apparatus and method for making optical measurements of a sample is described. In one embodiment, the apparatus is a microvolume sampling mechanism comprised of two opposing optical measurement surfaces. A sample is held by surface tension between the two opposing optical measurement surfaces. Light is transmitted through the sample and received by optical fibers, which measure the absorbance of the sample. This absorbance can be used to determine the concentration of the sample.