Wavelength scans of standard, blank and urine sample on Cd and Cr are illustrated in figure 3.
3. Seawater analysis
This study has shown that seawater samples can be analyzed directly following ultrasonic nebulization. To demonstrate the accuracy of the method, a known amount of analytes were added to the sample and the recovery calculated.
The dissolved solids content of seawater can be up to 3.5% w/v. Because of the relatively high salt content in seawater, it is recommended that longer washout times are required between samples to clean out any possible salt deposition in the injector tube and improve long term stability. The use of an auxiliary rinse, which delivers rinsing agent directly onto the transducer surface, can speed up the washout process and reduce the analysis time.
The results of the seawater analysis, the percentage spike recovery and the calculated detection limit (2 sigma) are given in table 3. The percentage recoveries ranged from 90103%. The precision of the measurements ranged from 0.5 to 3 %RSD.
Wavelength scans of 50 μg/L of Pb and Ni in seawater sample are shown in figure 4.
The Liberty ICP and ultrasonic nebulizer combination can be used for the direct determination of trace elements in samples such as urine and seawater. The measured values are in good agreement with the certified values and the percentage recoveries ranged from 90 to 103%.
1. ICP At Work No. 8, Nham T. T., Varian, Mulgrave, Victoria, 1992.
2. Determination of silicon, calcium, magnesium and phosphoru