, commonly employed in research labs, are used only for the studies mentioned above.
On the other hand, spectrophotometers and spectrofluorometers
can provide reasonable sensitivity, and they are inexpensive compared to ICP instruments.
Fruit fluorescing under laser-scanning confocal microscope Leica TCS SP-5 (laser excitation 405 nm): ((a) and (b)) single cells of fruit border on transverse slice, bar = 30 [micro]m, (c) excretion from the fruit, (d) the fluorescence spectra from (b) (cells emitted in green- yellow are marked by rings) and (c) images, (e) the fruit pulp, (f) secretory hair, (g) the fluorescence spectra from images (e) and (f), and (h) the fluorescence spectra registered by spectrofluorometer
Perkin Elmer 350 MPF-44B in 0.5 [cm.sup.3] cuvette from water solution of [10.sup.-5] M berberine.
In the lab, fluorescein standards ranging from 0.1-1.0 [micro]g [L.sup.-1] and a spectrofluorometer
(Perkin Elmer LS 55) established a standard curve for water analysis [Instrument settings: [lambda]ex = 488 nm; excitation = 2.5 nm, emission = 15 nm; scan 475-550 nm; scan speed = 200 nm [min.sup.-1]].
The fluorescence intensity of the samples was determined using Jasco FP-6200 spectrofluorometer
at 340 nm and 440 nm for the excitation and emission wavelengths, respectively.
The sensitivity of the spectrofluorometer
was evaluated before the field work.
Figure 2 shows a view of the spectrofluorometer
that was used to
The steady state fluorescence emission measurements were obtained using a commercially available spectrofluorometer
(Fluoromax-2, ISA; Jobin-Yuvon-Spex, Edison, NJ) and spectral band passes were kept as 5 nm in both excitation and emission monochromators.
The alteration in the fluorescence intensity was monitored by a PTI (MD-5020) dual wavelength spectrofluorometer
, by alternative excitation at 340/380 nm (PhoCal, Life Science Resources Ltd., Cambridge, UK).
Two replicates (0.4 mL) from each subsample were placed on a 96-well microwell plate and measured with a spectrofluorometer
(Varian Cary Eclipse).
A Horiba Fluorolog 2 (Horiba Scientific, Edison, NJ, USA) spectrofluorometer
was optically connected to the microwave delivery system via the optical guiding system (F-3000 Fiber Optic Mount, Horiba Scientific).