atomic absorption spectroscopy was used to determine the amount of aluminum in a sample of sunscreen. a standard solution of 1.00 ng al /l was prepared and measured seven times to determine the detection and quantitation limits of the spectrometer. the standard measurements were: 0.71, 0.90, 1.40 , 1.13 , 0.89 , 1.27 , and 0.99 ng al /l. calculate the detection and quantitation limits for this instrument.