PART C: KINETICS dilute the sample. If the From the Standard absorbance is Methods home still too high, screen, press 6 for dilute again Kinetics. and repeat until an Enter the accurate wavelength, delay measurement time (if any), is obtained. duration time, and Then, multiply interval length using the the numeric absorbance keypad and arrows. reading by the dilution factor Press the green to obtain the ► button to continue. absorbance of the original Select the concentration. measurement mode using the left Never use any and right arrows abrasive (you will most likely cleansers, want to select soaps, or Press the brushes on “Slope”). down arrow to get cuvettes. This to units, then enter can scratch the units manually them or leave or press the Options a button to choose contaminating from a list of units. residue. Press the down arrow and change Disposable the setting plastic “Factor” if you need to cuvettes can multiply results by a be used a few dilution factor. times before they become Press the green scratched or ► button to continue. stained and need to be Insert a cuvette discarded. containing the Clean these reference sample carefully and and press the they will last 0A/100%T button to for several take a blank uses. reading. Quartz cuvettes look Insert a cuvette like glass and containing the are made to sample and press have a long
PART C: KINETICS From the Standard Methods home screen, press 6 for Kinetics. Enter the wavelength, delay time (if any), duration time, and interval length using the numeric keypad and arrows. Press the green ► button to continue. Select the measurement mode using the left and right arrows (you will most likely want to select “Slope”). Press the down arrow to get to units, then enter the units manually or press the Options button to choose from a list of units. Press the down arrow and change the “Factor” setting if you need to multiply results by a dilution factor. Press the green ► button to continue. Insert a cuvette containing the reference sample and press the 0A/100%T button to take a blank reading. Insert a cuvette containing the sample and press dilute the sample. If the absorbance is still too high, dilute again and repeat until an accurate measurement is obtained. Then, multiply the absorbance reading by the dilution factor to obtain the absorbance of the original concentration. Never use any abrasive cleansers, soaps, or brushes on cuvettes. This can scratch them or leave a contaminating residue. Disposable plastic cuvettes can be used a few times before they become scratched or stained and need to be discarded. Clean these carefully and they will last for several uses. Quartz cuvettes look like glass and are made to have a long
2012_fall_sop_book_9th_ed_1.docx