Nanopores are increasingly utilized as tools for single molecule detection in biotechnology. Here, we report an improved fabrication process to make solid-state nanopores from glass tubes with the help of paraffin. Based on the physical footprint of the phase change of the paraffin, nanocavity is formed in the broken terminal after thermally compressing and pulling the glass capillary. Nanopores with the minimum diameter of 50 nm are fabricated. Different immunoglobulin molecules including IgG, IgA, IgM mixed in a 10 mM KCl solution are used to test the sensing capabilities of the glass-nanopore sensor. Various modulated ionic current modes were observed while the the three type immunoglobulin molecules translocate the nanopore because the molecules had different size and structure. Based on the difference in the duration time and amplitude of the transient electrical pulse signals, we are able to discriminate the three immunoglobulin molecules.