Cranberry Juice Experiment Lab Report

An experiment was carried out to determine the percent of 100 percent cranberry juice in cranberry apple juice. This experiment is significant in everyday chemistry because it is the job of many chemists, in regulatory agencies such as the FDA, to quantitatively determine if the ingredients listed on the label of a substance are actually in that substance. Cranberry juice has particular qualities that are not found in other juices. The quality studied in this experiment was color. Cranberry apple juice is a mixture, but, because it is said to contain cranberry juice, it should also have some of the same unique identifying quality, color, that cranberry juice has. In the experiment, a calibration curve, or standard curve to which an unknown can be compared, was …show more content…
The optimal wavelength of maximum cranberry juice absorption was determined to be 525 nm. The calibration curve could then be created by measuring the absorbance of known concentrations, 5% to 25%, of cranberry juice at 525 nm, and generating a calibration curve of absorbance vs concentration. The absorbance of the cranberry apple juice was then measured at the wavelength of maximum absorbance. Absorbance is a measure of the amount of light that passes through a sample at a selected wavelength. The absorbance is measured by the spectrophotometer 20 which functions by emitting a visible light source through the sample. This experiment used visible light because the probed molecule has an absorbance in the visible region of the spectrum. The Spectronic 20 is composed of a light source which in this case is a tungsten bulb, a wavelength selector, which selects the narrow bandwidth of light that passes through the sample, the sampler holder, and the detector, which captures the amount of light transmitted through the