A solution containing3.47mMX(analyte) and1.72mMS(standard) gave peak areas of3473and 10222,respectively, in a chromatographic analysis. Then1.00mLof 8.47mMSwas added to5.00mLof unknownX,and the mixture was diluted to10.00mL. This solution gave peak areas of5428and4431forXandS, respectively.

(a) Calculate the response factor for the analyte.

(b) Find the concentration of S(mM)inthe10.0-mLmixture.

(c) Find the concentration of X(mM)inthe10.0-mLmixture.

(d) Find the concentration ofXintheorignalunknown.

Short Answer

Expert verified

(a) The response factor for the analyte is 0.1684

(b) The concentration ofSmMis0.847mM

(c) The concentration of XmMis6.16mM

(d) The concentration of Xin the original unknown is12.32mM

Step by step solution

01

Definition of the equestion 

In this task, we have a solution that contains3.47mM×analyteand1.72mMS(standard)and yields chromatographic peak areas of 3473and10222.1mLof 8.47mMSwas mixed with 5mLof Xrunknown and diluted to $ 10mL, yielding peak areas of 5428and 4431for XandS,respectively.

02

Step 2:

(a)

The:#c34632''>responsefactoreresponsefactorfortheanalytewillbecalculatedhere.AxX=FASS3.4733.47mM=F102221.72mMF=0.1684Theresponsefactorfortheanalyteis0.1684

03

The concentration of S(mM) in 10mL the mixture

(b)

TheconcentrationofSmMinthe10mLmixtureis:S=8.47mM×1mL10mL=0.847mMTheconcentrationofSmMis0.847mM

04

The concentration of X(mM) in the 10mL mixture

(c)

TheconcentrationofXmMinthe10mLmixtureis:

AxX=FAS[S]5428[X]=0.168444310.847mM[X]=6.16mMTheconcentrationofX(mM)is6.16mM

05

Concentration of in the original unknown

(d)Theconcentrationofxintheoriginalunknownis:Theoriginalconcentration=2×dilutedconcentration=2.6.16mM=12.32mMTheconcentrationofxintheoriginalunknownis12.32mM

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.

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

What is the difference between a false positive and a false negative?

Here is a use objective for a chemical analysis to be performed at a drinking water purification plant: "Data and results collected quarterly shall will be used to determine whether the concentrations of haloacetates in the treated water demonstrate compliance with the levels set by the Stage 1 Disinfection By-products Rule using Method 552.2"(a specification that sets precision, accuracy, and other requirements).

Which one of the following questions best summarizes the meaning of the use objective?

(i) Are haloacetate concentrations known within specified precision and accuracy?

(ii) Are thehaloacetates detectable in the water?

(iii) Dothehaloacetate concentrations exceed the regulatory limit?

Europium is a lanthanide element found at parts per billion levels in natural waters. It can be measured from the intensity of orange light emitted when a solution is illuminated with ultraviolet radiation. Certain organic compounds that bindEu(III)are required to enhance the emission. The figure shows standard addition experiments in which10.00mLof sample and20.00mLcontaining a large excess of organic additive were placed in 50-mL volumetric flasks. Then Eu(III) standards (0,5.00,10.00,or15.00mL) were added and the flasks were diluted to50.0mLwithH2O. Standards added to tap water contained0.152ng/mL(ppb) of Eu(III), but those added to pond water were 100 times more concentrated (15.2 ng/mL).


(a) Calculate the concentration of Eu(III)(ng/mL) in pond water and tap water.

(b) For tap water, emission peak area increases by.4.61units when 10.00mL of 0.152ng/mL standard are added. This response is4.61 units/1.52ng = 3.03units per ng ofEu(III). For pond water, the response is12.5units when10.00mLof15.2ng/mLstandard are added, or0.0822units per ng. How would you explain these observations? Why was standard addition necessary for this analysis?

What is the difference between repeatability and reproducibility? Define the following terms: instrument precision, intra-assay precision, intermediate precision, and interlaboratory precision. Which type of precision is a synonym for reproducibility?

State when standard additions and internal standards, instead of a calibration curve, are desirable, and why.

See all solutions

Recommended explanations on Chemistry Textbooks

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