1. A forensic investigation was carried out to determine the amount of gun-shot residue on a small piece of fabric taken from clothing obtained at a crime scene. A two hour metallic ion extraction using 20 mL of a 15% acetic acid solution was carried out, with atomic absorption spectroscopy used to quantify the amount of barium deposited in the fabric. A 1000 mg/L barium stock solution was used to prepare standard solutions of the dilutions 1:200, 1:100, 1:50, 1:20 and 1:10. The response from the spectrometer in arbitrary units was 10.8, 21.9, 37.4, 99.2 and 207.8 respectively for the standards and 17.1 for the sample solution. (a) Calculate the concentration of barium in the sample solution and hence the total amount of barium recovered from the fabric.

1. A forensic investigation was carried out to determine the amount of gun-shot residue on a small piece of fabric taken from clothing obtained at a crime scene. A two hour metallic ion extraction using 20 mL of a 15% acetic acid solution was carried out, with atomic absorption spectroscopy used to quantify the amount of barium deposited in the fabric. A 1000 mg/L barium stock solution was used to prepare standard solutions of the dilutions 1:200, 1:100, 1:50, 1:20 and 1:10. The response from the spectrometer in arbitrary units was 10.8, 21.9, 37.4, 99.2 and 207.8 respectively for the standards and 17.1 for the sample solution. (a) Calculate the concentration of barium in the sample solution and hence the total amount of barium recovered from the fabric.

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 1.11QAP

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