Dating bloodstains with fluorescence lifetime measurements of a twin

Dating bloodstains with fluorescence lifetime measurements of a twin

Fluorescence lifetime measurements

In one embodiment, blood age is determined using the methods of the present disclosure. By limiting excitation and emission wavelengths as described above, however, fluorescence lifetime values of the tryptophan could be preferentially collected. Since the de-excitation process is associated with an energetically unstable state, fluorescence lifetime is highly sensitive to a great variety of factors. The method comprises measuring a fluorescence lifetime value of the blood sample.

Buffer is mixed with the sample to eliminate any effects due to pH and other environmental factors. One way to overcome some of the problems might be to combine readings from several different fluorescent molecules.

In another embodiment, the fluorescence lifetime value is determined through the presence of one or more of an organic quencher and an inorganic quencher. The instrument response function was obtained using a Rayleigh scatter of Ludox in water in a quartz cuvette at nm emission. As the environment changes and the proteins age, the fluorescence lifetime decreases. However, he raises concerns about the robustness of the technique. The blood was left exposed to room air and ambient light.

Amino acid residues give away bloodstain's age

In yet anotherAccordingly there is

The fit dashed lined was calculated from the two-phase decay modeling. The methods analyze the degradation of proteins, and thus the fluorescence lifetime of tryptophan, in blood to reflect the blood age. It is now believed that this variance allows for monitoring of blood degradation with fluorescence lifetime. If that can be done, the technique would have several advantages. These excitations may contaminate the tryptophan decay kinetics and thus may complicate the lifetime data analysis.

But then a new type ofSuch an approach will

Such an approach will minimize the problems with sampling and provide more accurate results. Fluorescence lifetime measurements can be measured using any fluorescence lifetime instrument known in the art. But then a new type of laser became available, with a wavelength of nm. Accordingly, there is a need in the art for an accurate method of determining blood age. In yet another embodiment, the present disclosure is directed to a method for determining the age of a blood sample.

Any buffer known in the art is suitable for use in the present methods. In one embodiment, the sample is mixed with a buffer.

In one embodiment blood age