Patent ID: 6261848
Filing Date: 2001-07-17
Classification: B01L,G01N

Abstract:
A hand held, self-contained, automatic sensor for detecting and quantifying the amount of aflatoxin in a sample, the sensor comprising:a power supply in the sensor;digital means powered by the power supply for automatically controlling the operation of the sensor;an external port for receiving the sample;a peristaltic pump for driving fluids in the sensor after the sample is received;an affinity column for binding and concentrating the aflatoxin contained in the sample;a first reservoir containing a fluid for rinsing the affinity column clean of any dissolved or suspended material other than the bound aflatoxin;a second reservoir containing an elution fluid for releasing the aflatoxin from the affinity column;a fluorometric cuvette for receiving the elution fluid containing the aflatoxin to be detected;an arc lamp for illuminating the fluorometric cuvette with radiation;a first optical system for collecting the radiation from the arc lamp and focusing the radiation on the fluorometric cuvette and the elution fluid containing the aflatoxin therein;an ultraviolet filter positioned between the first optical system and the fluorometric cuvette for removing radiation received from the first optical system except primarily radiation within a band in the near ultraviolet that excites fluorescence associated with the aflatoxin thereby causing the aflatoxin to emit a blue fluorescent light in the fluorometric cuvette;a second optical system for collecting the radiation including the blue fluorescent light emitted by the aflatoxin in the fluorometric cuvette and focusing the blue fluorescent light on a photomultiplier tube;a second filter for passing only the blue fluorescent light emitted by the aflatoxin;a photomultiplier tube for converting the blue fluorescent light received from the second filter into electrical current, the total charge of the current being proportional to the amount of blue fluorescent light that is input to the photomultiplier tube and to the concentration of the aflatoxin in the elution fluid;a transimpedance amplifier having a low pass characteristic for converting the charge of the current from the photomultiplier tube into a pulse;an operational amplifier circuit having a low pass characteristic for receiving the pulse from the transimpedance amplifier;a switch, the switch when open holding a value that is a maximum in response to the pulse and when closed outputting the held value;means for digitizing the held value; andmeans for displaying the held value.