Abstract: Provided herein are methods, apparatuses, and systems for enhancing the detection of reactive gases, such as ethylene gas, that are present at low concentrations in air samples. The methods and systems enhance the selectivity, sensitivity, and accuracy of electrochemical cells by removing interfering gases from the air samples. Some systems include an ethylene sensor that includes an electrochemical cell and a polar solvent gas trap pre-filter, wherein the gas trap is positioned upstream of the electrochemical cell. Some methods are methods of measuring an ethylene level in an air sample, and include passing the air sample by through a polar solvent gas trap, and measuring the ethylene level in the air sample with an electrochemical cell.

Abstract: A document reader for reading manually fed edge coded documents, comprising a first component including a side wall, a second component orthogonally positioned with respect to the first component and having a second sidewall, the first and second sidewalls positioned adjacent one another so as to form a document receiving slot therebetween, the first sidewall containing an opening, a drive means, the drive means positioned within the first component and adapted to project through the first sidewall opening and substantially across the slot, the second sidewall including an opening, reading means contained within the second component, the reading means including a light source, means for directing light from the source through the second wall opening to the document, means responsive to light reflected from the document for converting the reflected light to digital data, control means coupled to the drive means, sensing means positioned proximate to the slot for sensing the precise location of the document, th