Firstly, the spectrophotometer wavelength was set to 640 nm. Secondly, the A/T/C button was pushed to select % transmittance, and the digital readout showed %T. Thirdly, one syringe was labeled for ethanol and another for leaf extract. Fourthly, 3 mL of ethanol was dispensed into a clean glass cuvette, making sure to wipe off fingerprints with a Kimwipe. Fifthly, the cuvette was inserted into the cell holder, and the door was closed. Sixthly, the 0 ABS/100%T key was pressed to set the blank to 100% transmittance. Seventhly, the blank, used as a standard, was removed, and 3 mL of the leaf extract was dispensed into a clean glass cuvette while ensuring that all fingerprints were wiped off. Eighthly, this cuvette was inserted into the cell holder, and the door was closed. Ninthly, the % transmittance was checked, noting that a reading of 30%-40% was ideal. Tenthly, if the %T exceeded 40%, the dilution step was skipped; if it fell below 30%, dilution was needed. Eleventhly, to dilute the extract, 0.5 mL of ethanol was added, and the cuvette was inverted to mix while a finger was held over the opening. Lastly, the percent transmittance was retested, continuing with 0.5 mL increments of ethanol until the reading exceeded 30% transmittance.
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 step by step how practical carried out by stating firstly, secondly, thirdly and ect according to process
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