Then, 0.3 mL of 0.5 M HClO4
was included in the mixture in order to precipitate the proteins.
Make: Merck Product Code 1.01203.0500, Potassium chloride solution( 12g L-1 in water) reference material for stray light testing (UV-VIS standard 4) Make: Merck Product Code 1.08164.0001, Holonium oxide solution (40 g Ho2O3/l in HClO4
(10% v/v)) Reference material for wave length calibration UV-VIS standard 6 Make: Merck Product Code 1.08166.0001,
Nitric acid is used commonly since it produces the fewest polyatomic interference in contrast to HClO4
Then shoots were rinsed with tap water and dipped into 70% alcohol for one minute and rinsed with HClO4
and distilled water.
Phosphate content in the plant was extracted with wet oxidation with HNO3dan HClO4
 and the concentration of P was measured with spectrometer (Vitatron Scientific Instruments Dieren, the Netherlands).
Plant material (leaves) was wet-digested in nitric acid (HNO3) and perchloric acid (HClO4
) which was in the ratio 0f 10:1 (V/V).
A known weight (0.5 g) of a dried powdered sample was digested using 3:1 mixture of concentrated HN[O.sub.3] (69-70.5%) and concentrated HClO4
(70%) under reflux at a temperature of 240[degrees]C for 2:30 hours.
Aliquots of sample were digested with a mixture of 4mL of HN[O.sub.3] (c) and 1mL HClO4
(Aldrich or Sigma Chem.
El N-total fue cuantificado por el metodo Kjeldahl (Digestor Novatech; USA y Micro Kjeldahl Labconco rapid destillation Unit, USA) (Jackson 1964); N-NO3 por el metodo de Brucina y espectrofotometria (HACH DR 5000-UV-visible) (UvalleBueno 1993), los iones Ca, Mg, K, Na, Cu, Fe, Mn y Zn mediante digestion con 25 ml de mezcla triaci da (HN[O.sub.3], HClO4
y H2SO4 en relacion 10:1:0.25) y espectrofotometro de absorcion atomica (Perkin Elmer Analyst 100); P-total mediante el metodo del vanadato-molibdato de amonio y analisis mediante espectrofotometria UV-visible, (Nogales et al.
A uranium standard solution (100 ppm (w/v)) was prepared from analytical reagent grade uranyl nitrate hexahydrate in 3 M of HClO4
. Arsenazo-III (0.07% w/v) solution was prepared in 3 M of HCl[O.sub.4].
Subsamples of the ground shoot (200mg) and root (100mg) were digested in a mixture of concentrated HNO3 and HclO4
(4:1 by volume) and the As, Cr and Cu in the digested solutions were determined by AAS.
On varying perchloric acid concentration from 0.1 to 0.5 mol[dm.sup.-3] the negative catalyzed kinetics was observed by the addition of HClO4
and first-order was evaluated (Table 3).