Assuming that GC-MS indicated the presence of acetaminophen, how does the GC-MS experimental evidence demonstrate that ELISA is not a confirmatory test for acetaminophen? Solution Using the chromatographic techniques of like TLC, HPLC & GC-MS the estimation of paracetamol is established procedure in analysis. And the ELISA (Enzyme-Linked Immuno Sorbent Assay) test kit is a qualitative one-step kit developed as a screening device for the detection of drugs as well as respective metabolites in a test sample. This kit was just designed for the screening of compounds and is widely used in forensic science. Furthermore it is recommended that all doubtful samples should be confirmed by gas chromatography/mass spectrometry (GC/MS). The Gas chromatography separates the components of a mixture & the mass spectroscopy characterizes individual components. Hence by combining these two techniques, we can analyze both qualitatively & quantitatively the test sample of any compound. Thus GC-MS experimental evidence demonstrates that ELISA is not a confirmatory test for acetaminophen. Itâ€™s just a qualitative technique. .