For an analysis of phthalates by GC-MS, the limits of detection and quantitation are 0.55 and 3.56 mg/g, respectively. Based on the results obtained below, how are the 3 samples reported? Sample Concentration (mg/g) A 4.50 B 0.055 C 0.56
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For an analysis of phthalates by GC-MS, the limits of detection and quantitation are 0.55 and 3.56 mg/g, respectively. Based on the results obtained below, how are the 3 samples reported?
Sample | Concentration (mg/g) |
A | 4.50 |
B | 0.055 |
C | 0.56 |
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- (Standard addition) Tooth enamel consists mainly of the mineral calcium hydroxyapatite, Ca10(PO4)6(OH)2. Trace elements in teeth of archeological specimen provide anthropologists with clues about diet and diseases of ancient people. Student at Dankook University measured the trace element strontium (Sr) in enamel from extracted wisdom teeth by atomic absorption spectroscopy. Solutions were prepared with a constant total volume of 10 mL containing 0.750 mg dissolved tooth enamel plus variable concentrations of added standard Sr. Added Standard Sr (ng/mL=ppb) 0 2.50 5.00 7.50 10.00 Emission Signal 28.0 34.3 42.8 51.5 58.6 (a) Make a graph showing the experimental data and the calculated straight line. (b) Find the concentration of Sr in the tooth ennamel in parts per million = μg/mL.An atomic absorption method for the determination of the amount of iron present in used jet engine oil was found from pooling 30 triplicate analyses to have a standard deviation s = 3.6 mg Fe/mL. If s is a good estimate of σ, calculate the 95 and 99% confidence intervals for the result 18.5 mg Fe/mL if it was based on (a) a single analysis, (b) the mean of two analyses, and (c) the mean of four analyses.In spectrophotometric analysis, the relationship between the absorbance A and the analyte's concentration C is: A = ebC + Ablank What is the molar extinction coefficient I and its absolute uncertainty if A is 0.68 ± 0.06; Ablank is 0.06 ± 0.01; b is 1.00 cm; and C is (0.45 ± 0.03)x10-5 mol/L?
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