theoretical values, and generated a list of proteins that matched at least 5 out of the 20 masses submitted. A second pass utilized Intellical to recalibrate the spectrum based on the first-pass results as a pseudo-internal calibration curve, and required experimentally measured masses to be within 30 ppm of the calculated values. A list of proteins that matched at least 4 out of the 20 peak masses submitted was generated. False-positive hits typically had a maximum of 4 or 5 peptides matched out of 20 masses submitted under the search conditions described.