不是考大家,我也不确定,请教大家: 1. Which of the following statements are true regarding ICP operating parameters: a) Excessive auxiliary gas flow can destabilize the plasma, resulting in poorer precision b) Nebulizer pressure has no effect on sample residence time (time within plasma excitation zone). c) "Drowning" the nebulizer with excessive sample uptake can contribute to a noisier emissions signal. d) All of the above are correct. e) Answers 'A' and 'C' only are correct.
2. Which of the following statements are(is) NOT true regarding ICP analysis: a) Viscosity differences in samples and/or standards can contribute to variation in analysis results. b) Drain lines should typically have a smaller inner diameter than the sample uptake lines to help promote aspiration of larger amounts of sample. c) Any element detectable by ICP analysis may be used as an internal standard provided it does not interfere with the elements being analyzed.
3. The following replicate data was obtained from a final 10-ppm check standard during ICP analysis. Fe Cu Mg Replicate #1 8.5269 8.4365 8.6358 Replicate#2 9.7852 9.6399 9.7987 Replicate#3 10.0263 9.9859 10.0024 What is(are) the potential cause(s) for the patterns seen in the readings? a) Instrument drift. b) Sample flush time. c) Lack of homogeneity of samples. d) All of the above. e) None of the above