Determination of small amounts of palladium in wastes from reworking of spent catalysts by microwave induced plasma atomic emission spectrometry

Microwave induced plasma atomic emission spectrometry (MIP-AES) was used for analytical control of reworking of catalysts. Palladium was determined in plant wastes after acid digestion in open systems or systems under pressure. The conditions for introduction of analyte solution using ultrasonic nebulisation and excitation of palladium in the low-power argon microwave plasma sustained in the TM010 Beenakker type resonator were established. The matrix effects of iron and nickel were studied. Palladium was determined using the argon flow-rate of 200 ml min−1 and 130 W of incident power and detection limit of about 65 μg l−1 in the matrix containing up to 5 mg ml−1 of interfering metals was achieved. A matrix matching method to obtain accurate results was finally applied. The wide linear dynamic range obtained (0.3–250 mg l−1) was useful for routine analysis. For samples with higher palladium content a spectrophotometric method was used as reference to assess the accuracy and precision of the determination by the MIP-AES technique. The low Pd level was tested by analysis of the reference material (platinum ore).