Purpose: The purpose of this laboratory experiment was to prepare morphine samples via solid phase extraction, and then analyze them using gas chromatography and mass spectroscopy methods. This was done in order to determine the concentration of one unknown sample, interpreting the results based on a generated calibration curve from the GCMS data. Procedure: • Prepare buffers and a calibration curve: o 100 mL of 100 M phosphate buffer with pH 6.00 0.2 using 1.182 g KH2PO4 and 0.1867 g Na2HPO4 o 100 mL of 100 M acetate buffer with pH 4.5 0.2 using 0.291 g NaOAc and 6.454 mL acetic acid o calibration solutions to generate a curve with the points 2, 10, 30, 50, and 80 g/mL o provided internal standard Test buffers with pH meter. Store in …show more content…
mL acid needed: 6.454 mL Moles of Base for 0.1 L = 0.003546 Na2HPO4 weighed: 0.1867 (±0.0001) g KH2PO4 weighed: 1.1828 (±0.0001) g pH of phosphate buffer was calibrated and analyzed to be 5.97-6.1 pH NaOAc weighted: 0.2913 (±0.0001) g pH of acetate buffer calibrated and analyzed to be 4.35-4.45 pH Calibration Points and Pipette Errors When Preparing Samples: 2, 10, 30, 50, 80 µg/µL needed for the first calibration point diluted to stock of 100 µL 40 (±1.0) µL of 2 + 1000 (±5.0) µL buffer + 10 µL (±0.1) internal standard + 400 (±5.0) µL buffer = 1450 (±11.1) µL sample needed for the first calibration point diluted to stock of 100 µL 40 (±1.0) µL of 10 + 1000 (±5.0) µL buffer + 10 µL (±0.1) internal standard + 400 (±5.0) µL buffer = 1450 (±11.1) µL sample needed for the first calibration point diluted to stock of 100 µL 40 (±1.0) µL of 30 + 1000 (±5.0) µL buffer + 10 µL (±0.1) internal standard + 400 (±5.0) µL buffer = 1450 (±11.1) µL sample needed for the first calibration point diluted to stock of 100 µL 40 (±1.0) µL of 50 + 1000 (±5.0) µL buffer + 10 µL (±0.1) internal standard + 400 (±5.0) µL buffer = 1450 (±11.1) µL sample needed for the first calibration point diluted to stock of 100 …show more content…
This is necessary for the development of the calibration curve, as the internal standard allows for the ratio comparison between standard and sample. By plotting these ratio values (note: see results, calculations, and analysis section) against the known concentrations, a calibration curve can be created and used to determine the concentration of unknown samples (note: see comments section for possible errors in ratio and calibration curve values). Using the best fit for the plotted curve, the produced equation, y = 0.0244x – 0.0133 (where y = ratio standard/sample and x = concentration), was used to determine the concentration of the unknown sample, which was calculated to be approximately 38.73