Low concentrations of warfarin near the detection limit gave the dimensionless instrument readings: 195.5, 166.9, 152.5, 164.5, 209.5, 150.3, 213.3, 191.9, 124.9, and 195.7. Ten blanks had a mean reading of 40.7. The slope of the calibration curve is 3.09 x 10° M-¹. Estimate the signal and concentration detection limits and the lower limit of quantitation for warfarin.

Low concentrations of warfarin near the detection limit gave the dimensionless instrument readings: 195.5, 166.9, 152.5, 164.5, 209.5, 150.3, 213.3, 191.9, 124.9, and 195.7. Ten blanks had a mean reading of 40.7. The slope of the calibration curve is 3.09 x 10° M-¹. Estimate the signal and concentration detection limits and the lower limit of quantitation for warfarin.

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter1: Introduction

Section: Chapter Questions

Problem 1.9QAP

See similar textbooks

Similar questions

Mass spectrometry is an extremely versatile detection system for GC. However, interfacing an HPLC system to a mass spectrometer is a much more difficult task. Describe the major reasons why it is more difficult to combine HPLC with mass spectrometry than it is to combine GC with mass spectrometry.
Inductively coupled plasma–optical emission spectrometry (ICP-OES) was used for the determination of cadmium using indium as an internal standard. A solution containing 2.15 ppm Cd2+ and 5.76 ppm In3+ gave signals of 19,291 and 37,190 counts for cadmium and indium, respectively. A 0.01652 g sample was dissolved in acid and quantitatively transferred to a 250.0 mL volumetric flask. A 1.00 mL aliquot of 264.5 ppm In3+ was added and the flask was diluted to volume with deionized water. ICP-OES analysis of the sample solution gave signals of 31,109 and 118,941 counts for cadmium and indium, respectively. What was concentration of the Cd2+ in the sample? Give answer all questions with explanation
Chemistry Atomic absorption analysis of Zn gave a calibration best fit line of A=0.670(ppm Zn) The detection limit was determined for this analysis using a 0.020 ppm Zn solution. The standard deviation of the absorbances for 11 samples of the solution was found to be 1.560 x 10-3 and the slope of the calibration curve was 0.026. Calculate the detection limit, Cq, (in units of ppm) for this instrument. Give your answer to 3 places after the decimal place.
A spectrophotometer method for the quantitative analysis of Pb2+ in blood uses Cu2+ as an internal standard. A standard containing 1.75 ppb Pb2+ and 2.25 ppb Cu2+ yields a signal of 0.832 for Pb2+ and a signal of 0.351 for Cu2+. A sample of blood is spiked with the same concentration of Cu2+, giving a signal of 0.520 for Pb2+ and 0.289 for Cu2+. Determine the concentration of Pb2+ in the sample of blood.
Seawater was spiked with phosphate to achieve a quantifiable range of phosphate concentrations by spectroscopy. What components of the spectrophotometer or sample preparation could be changed that would improve detection limits?
In the process of performing a spectrophotometric determination of Fe, an analyst prepares a calibration curve using a single-beam spectrometer, such as a Spec-20. After preparing the calibration curve, the analyst drops the cuvette used for the method blank and the standards. The analyst acquires a new cuvette, measures the absorbance of the sample, and determines the %w/w Fe in the sample. Will the change in cuvette lead to a determinate error in the analysis? Explain.
Standard solutions of a chemical species with different concentrations are analyzed using a UV-Vis spectrophotometer. The absorbance values obtained are plotted against concentration and the slope of the drawn calibration line is calculated as 55400. Since a 0.5 cm cuvette is used in this analysis, calculate the molar absorptivity coefficient of the analyzed species.
Seawater was spiked with phosphate to achieve a quantifiable range of phosphate concentrations by the spectrophotometer. What components of the spectrophotometer or sample preparation could be changed that would improve detection limits?