Question
Procedure:
1. Set the spectrophotometer wavelength to 640 nm.
2. Push the A/T/C button to select % transmittance. The digital readout will show %T.
3. Label one of the 3 mL syringes ethanol. Label the second syringe leaf extract.
4. Dispense 3 mL of ethanol into a clean glass cuvette. (Wipe off finger prints with a Kimwipe.)
Important: This cuvette is a “blank” that will be used throughout this lab to calibrate the
spectrophometer.
5. Insert the blank in the cell holder and close the door.
6. Press the 0 ABS/100%T key to set the blank to 100% transmittance.
7. The blank provides a standard for reading. Remove the blank and proceed with testing the
extract by following the same procedure.
8. Dispense 3 mL of the extract into a clean glass cuvette. (Wipe off all fingerprints with a
Kimwipe.)
9. Insert the cuvette in the cell holder and close the door.
10. A reading of 30%-40% transmittance is best. If %T is greater than 40%, you may skip the dilution step. If it shows less than 30% transmittance, dilution of the sample is required.
11. To dilute the filtered extract, add 0.5 mL of ethanol (using the clean ethanol syringe).
Tightly hold a finger over the cuvette and invert to mix. Re-test the percent transmittance. Continue with 0.5 mL increments of ethanol until the reading is greater than 30% transmittance
Write it in one paragraph using simple English terms and don't use noun or pronoun. Write it in past tense
1. Set the spectrophotometer wavelength to 640 nm.
2. Push the A/T/C button to select % transmittance. The digital readout will show %T.
3. Label one of the 3 mL syringes ethanol. Label the second syringe leaf extract.
4. Dispense 3 mL of ethanol into a clean glass cuvette. (Wipe off finger prints with a Kimwipe.)
Important: This cuvette is a “blank” that will be used throughout this lab to calibrate the
spectrophometer.
5. Insert the blank in the cell holder and close the door.
6. Press the 0 ABS/100%T key to set the blank to 100% transmittance.
7. The blank provides a standard for reading. Remove the blank and proceed with testing the
extract by following the same procedure.
8. Dispense 3 mL of the extract into a clean glass cuvette. (Wipe off all fingerprints with a
Kimwipe.)
9. Insert the cuvette in the cell holder and close the door.
10. A reading of 30%-40% transmittance is best. If %T is greater than 40%, you may skip the dilution step. If it shows less than 30% transmittance, dilution of the sample is required.
11. To dilute the filtered extract, add 0.5 mL of ethanol (using the clean ethanol syringe).
Tightly hold a finger over the cuvette and invert to mix. Re-test the percent transmittance. Continue with 0.5 mL increments of ethanol until the reading is greater than 30% transmittance
Write it in one paragraph using simple English terms and don't use noun or pronoun. Write it in past tense
Answers
Answered by
GPT-4o mini
The spectrophotometer was set to a wavelength of 640 nm, and the % transmittance was selected by pressing the A/T/C button, displaying %T on the screen. One of the 3 mL syringes was labeled for ethanol and another for leaf extract. Three mL of ethanol was dispensed into a clean glass cuvette, ensuring fingerprints were wiped off with a Kimwipe. This cuvette served as a "blank" for calibration of the spectrophotometer. The blank was inserted into the cell holder, the door was closed, and the 0 ABS/100%T key was pressed to establish 100% transmittance. After removing the blank, three mL of the extract was dispensed into a new cuvette, with careful fingerprint cleaning. The cuvette was inserted again into the cell holder, and a reading was obtained. If the %T reading was between 30% and 40%, no dilution was necessary. Readings above 40% allowed for skipping dilution, while readings below 30% required dilution, achieved by adding 0.5 mL of ethanol using the ethanol syringe, mixing by inverting with a finger over the cuvette, and re-testing until the reading exceeded 30%.