Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 22: Q3P (page 559)

Bone consists of the protein collagen and the mineral hydroxyapatite,Ca10(PO4)6(OH)2The content of archaeological human skeletons measured by graphite furnace atomic absorption sheds light on customs and economic status of individuals in historical times 37 . Explain whyLa3+is added to bone samples to suppress matrix interference in analysis.

Short Answer

Expert verified

La3+appears to be a releasing agent, as it preferentially reacts withPO42-,releasingPb2+

Step by step solution

01

Define release agent.

A release agent (also known as a release coating, release agent, or mould release coating) is a substance that prevents other materials from adhering to surfaces. Mould release, die-cast release, plastic release, adhesive release, tyre and web release are all procedures where it can help.

02

Explain why La3+is added to bone samples to suppress matrix interference in  Pb analysis.

To avoid the chemical matrix effect,La3+is employed. By creating thermally stable compounds,PO42-prevents the atomization ofPb2+.La3+appears to be a releasing agent, as it preferentially reacts withPo42-, releasingPb2-

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The molecular ion region in the mass spectrum of a large molecule, such as a protein, consists of a cluster of peaks differing by 1 Da. This pattern occurs because a molecule with many atoms has a high probability of containing one or several atoms of C1315N,18O,2Hand 32S. In fact, the probability of finding a molecule with only C1214N,16O,1Hand 32S may be so small that the nominal molecular ion is not observed. The electrospray mass spectrum of the rat protein interleukin-8 consists of a series of clusters of peaks arising from intact molecular ions with different charge. One cluster has peaks at m/z 1 961.12, 1 961.35, 1 961.63, 1 961.88, 1 962.12 (tallest peak), 1 962.36, 1 962.60, 1 962.87, 1 963.10, 1 963.34, 1 963.59, 1 963.85, and 1 964.09. These peaks correspond to isotopic ions differing by 1 Da. From the observed peak separation, fi nd the charge of the ions in this cluster. From m/z of the tallest peak, estimate the molecular mass of the protein.

Bone consists of the protein collagen and the mineral hydroxyapatite,Ca10(PO4)6(OH)2. The content of archaeological humanskeletons measured by graphite furnace atomic absorption shedslight on customs and economic status of individuals in historicaltimes. 37Explain why La3+ is added to bone samples to suppressmatrix interference in Pbanalysis.

Explain what is meant by spectral, chemical, ionization, andisobaric interference.

Quantitative analysis by selected ion monitoring. Caffeine in beverages and urine can be measured by adding caffeine- D3as an internal standard and using selected ion monitoring to measure each compound by gas chromatography. The figure shows mass chromatograms of caffeine (m/z,194)and caffeine-DD3(m-z.197), which have nearly the same retention time.

Suppose that the following data were obtained for standard mixtures:

(a) Compute the mean response factor in the equation

role="math" localid="1664874599903" AreaofanalytesignalAreaofstandardsingle=F(concentrationofanalyteconcentrationofstandard)

(b) For analysis of a cola beverage, 1.000mL of beverage was treated with 50.0μLof standard solution containing 1.11 g/Lcaffeine-D3 in methanol. The combined solution was passed through a solid-phase extraction cartridge that retains caffeine. Polar solutes were washed off with water. Then the caffeine was washed off the cartridge with an organic solvent and the solvent was evaporated to dryness. The residue was dissolved in50μL of methanol for gas chromatography. Peak areas were 1144 for m/z197 and 1733 for m/z194. Find the concentration of caffeine (mg/L ) in the beverage.

Measure the width at half-height of the peak at m/z53and calculate the resolving power of the spectrometer from the expression m/m1/2. Would you expect to be able to resolve two peaks at 100and 101Da?
See all solutions

Recommended explanations on Chemistry Textbooks

Organic Chemistry

Read Explanation

Ionic and Molecular Compounds

Read Explanation

The Earths Atmosphere

Read Explanation

Chemical Analysis

Read Explanation

Physical Chemistry

Read Explanation

Chemical Reactions

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free