Methods and apparatus for measuring analytes

摘要

Methods and apparatus relating to FET arrays including large FET arrays for monitoring chemical and/or biological reactions such as nucleic acid sequencing-by-synthesis reactions. Some methods provided herein relate to improving signal (and also signal to noise ratio) from released hydrogen ions during nucleic acid sequencing reactions.

主权项

1. A system for chemical analysis comprising:
an array of pixels having a plurality of rows and a plurality of columns, each of the pixels having a reaction area and a chemically sensitive sensor that provides an analog output indicative of a reaction occurring proximate to the reaction area for the pixel; a selection circuit arranged to select at least one of the rows; a plurality of column circuits, each column circuit arranged to receive the analog output from a selected row during a first sampling period; a multiplexer to receive a plurality of analog outputs from the array of pixels via the plurality of column circuits; an analog to digital conversion circuit to
receive the plurality of analog outputs from the multiplexer,sample the analog outputs from the multiplexer at a second rate that is greater than the first rate, andgenerate a series of samples for each of the analog outputs at the second rate for a second sampling period that corresponds to the first sampling period; and an estimation device to receive the series of samples and determine an estimated pixel value from the series of samples during the first sampling period, wherein the analog output changes gradually to reach a final pixel value during the first sampling period as reactions within the reaction area are sensed by the chemically sensitive sensor and the estimated pixel value is an estimation of the final pixel value.