How to Measure Absorbance

Spectrophotometer - Ultrospec™ 3100pro

First check that the spectrophotometer is on – otherwise switch it on at the rear of the unit.
Exit from any applications by pressing stop repeatedly until Ultrospec™ 3100pro is shown at the top of the screen. Press enter to select Yes at the dialog box asking for confirmation to exit from the current application.
Use the ◄ and ► keys to navigate to the Basic tab sheet.
Press ▼ to select the tab sheet.
Use the ◄ and ► keys to navigate to the Absorbance tab sheet.
Press ▼ to select the function.
Press ▼ to highlight the wavelength edit box.
Use the keypad to enter the desired wavelength.
Press ▼ twice to enter the absorbance screen.
Place the reference cuvette in the blue holder (light path is from left to right).
Place the sample(s) in one or more of the following holders (2, 3, 4…). If using the same cuvette for both reference and sample, place only the reference and move the cuvette to position 2 after zeroing.
Press run to zero on the reference.
Press run one or more times to measure the sample absorbance(s).
To return to the reference for a new set of samples at any time, press C .
To move to any sample, press the corresponding key on the keypad.
To exit the application and return to the main screen, press stop twice.

First check that the spectrophotometer is on – otherwise switch it on at the rear of the unit.
Exit from any applications by pressing stop repeatedly until Ultrospec™ 3100pro is shown at the top of the screen. Press enter to select Yes at the dialog box asking for confirmation to exit from the current application.
Use the ◄ and ► keys to navigate to the Methods tab sheet.
Press ▼ to select the tab sheet.
Use the ◄and ► keys to navigate to the 1-10 tab sheet.
Select the desired Bradford standard curve (e.g. “Bradford BSA 0-5 μg”) by pressing the corresponding number on the keypad.
Place the reference cuvette (Bradford dye with no protein added) in the blue holder (light path is from left to right).
Place the Bradfordsample(s) in one or more of the following holders (2, 3, 4…)
Press run to start.
Press enter to select No at the dialog box asking if new standards are being loaded.
The instrument will now zero on the reference and measure the absorbance of position 2. The number of μg protein in the sample will be shown in the Concentration field.
Press run to measure the absorbance of any subsequent samples.
To return to the reference for a new set of samples at any time, press C .
To exit the application and return to the main screen, press stop and then enter to select Yes at the dialog box asking for confirmation to exit from the current application.
Press stop again to return to the main screen.