The content of the flask were brought to volume with water and added 2ml of 2N HNO3
and brought to flam atomic absorption spectrophotometer.
The precision of the analytical procedures was expressed as relative standard deviation (RSD) which ranged from 5% to 10% and was calculated from the standard deviation divided by the mean The working solutions were daily prepared by appropriate dilutions of the standard stock solution, using a mixture of 65% (v/v) HNO3
, 30% (v/v) H2O2 and H2O (v/v/v = 1:1:3).
In the pH effect experiment, the desired solution pH was first adjusted by HNO3
5 ml of concentrated H2SO4 and 4ml of concentrated HNO3
solution was used as the desorbing solution and the adsorption capacities remain stable after three adsorptions and desorption respectively .
The pH of the samples was adjusted to about 2 by adding 5 ml concentrated HNO3
and the samples were transferred 500 ml polypropylene bottle and stored in a refrigerator until the measurement process.
Tenders invited for Cross- woven teflon tube, 5-strandnullgarland type tubular heater forsteam heating of hf+ hno3
picklingnullbath as per the annexure attached
The elution of copper ions retained on the adsorbent was carried out with 3 mL of 1 mol/L HNO3
Sample (2 g) was weighed in digestive tube to which 4 ml HNO3
was added and covered with small funnel in the fume hood.
Picric acid Mn(NO3)24H2O Co(NO3)26H2O Cu(NO3)23H2O Zn(NO3)26H2O Pb(NO3)2 HNO3
NaNO3 CH3COOH CH3COONa dichloromethane and chloroform were purchased from Merck.
5 g) of shoots and roots were digested in concentrated HNO3
(5 mL) at 100C temperature and then raised the temperature at150C in digestion tubes and then made volume of the extracted up to 50 mL in the volumetric flask.
Soil samples were digested with concentrated HCl +concentrated HNO3
+ HF + HClO4 (10:5:5:3, v/v) and plant tissues (fruits and leaves) digested with concentrated HNO3
-H2O2 acid mixture (2:3 v/v) in three step (first step; 145oC, 75%RF, 5 min; second step; 180oC, 90%RF, 10 min and third step; 100oC, 40%RF, 10 min) in microwave (Bergof Speedwave Microwave Digestion Equipment MWS-2) (Mertens 2005a).