A method is provided for the determination of NO2\u2212 andor NO3\u2212 in water by subjecting the water sample to ultraviolet resonance Raman spectroscopy within the range of wavelengths of 200-240 nm, and determining the presence of NO2\u2212 andor NO3\u2212 based on the Raman spectral measurement. Connected to the lower longitudinal edges of the collision plates are support plates which extend from the base body outwards. The modulus of the body cords is configured to be larger in the lower section than in the upper section. The packaging cells contain at least three vectors which collectively encode retroviral gag, pol, and env proteins, wherein the gag and pol genes are separated, in part, onto two or more different vectors.