Homework assigment:
Chapter Chapter Problems Problems
1
1, 11, inst (x3)
5
2, 5, 7, 9, inst (x1)
Department of Chemistry and Biochemistry The College at Brockport, SUNY CHM 44! "nstr#mental Methods "" Dr$ M$ Bro%n Chapter Home%ork &re'$ ()*+4
Chapter 1- Instructor Problems
Chapter 1Question 1-1:
What is a transducer in an analytical instrument? The term transducer refers specifically to those de'ices that con'ert information in nonelectrical domains to information in electrical domains and the con'erse$ -.amples incl#de photodiodes, photom#ltipliers, and other electronic photodetectors that prod#ce c#rrent or 'oltage proportional to the radiant po%er of electromagnetic radiation that falls on their s#rfaces$ /ther e.amples incl#de thermistors, strain ga#ges, and Hall effect &magnetic0lield strength transd#cers$ 1s s#ggested pre'io#sly$
Question 11: Exactly 5.-m! ali"uots o# a solution containin$ phenobarbital %ere measured into 5.-m! &olumetric #las's and made basic %ith ()*. +he #ollo%in$ &olumes o# a standard solution o# phenobarbital containin$ ,. µg/mL o# phenoharhital %ere then introduced into each #las' and the mixture %as diluted to &olume . .5 1. 1.5 and ,. m!. +he #luorescence o# each o# these solutions %as measured %ith a #luorometer %hich $a&e &alues o# /.,0 .2 0.1 2., and 3.50 respecti&ely. 4a Plot the data. 64b 7sin$ the plot #rom 4a calculate the concentration o# phenoharbital in the un'no%n. 64c 8eri&e a least-s"uares e"uation #or the data. 64d 9ind the concentration o# phenobarbital #rom the e"uation in 4c. 4e Calculate a standard de&iation #or the concentration obtained in 4d.
a data set
LINES T
n 1
(Vs) x (mL) 0
(LS4x) y (Abs) 3.260
m sm
2 3
0.5 1
4.8 6.41
R2 F
4 5 6
1.5 2
8.02 Ssreg 9.56
N& $! intere/#m L%& i#%& s#%
Sxx= 5
3.164 0.016 0.999 9 3830
3.246 0.02 0.025 56 3
25
0
b sb sy df ssresi d
2.5
!1.03 0.410 0.004 4 10.000 9.000
"#$% & 3.16$ ' 3.25 () & 1
8.000 .000 6.000 5.000
uorescence
4.000 3.000 2.000 1.000 !2
!1
0.000
0
1
2
*o+,me o" Stan-ar- a--e- #m L%
3
% Te e,ation 7 & 3.164$ ' 3.246 omine- wit te a+,e 5 m+ o" ,nknown so+,tion# * $ & 5 m+% tat ontaining /enoarita+ an- signa+ o" te origina+ stan-aronentration S i& 2.000 µg/mL we can obtain the onentration o" /enoarita+ in te ,nknown tat is i#%& 0.410 µg/mL. C) 7 & 3.164$ ' 3.246 % i#%& 0.410 e% Stan-ar- -eiation & 0.041 ;0.044 1. !ist three output transducers #ound in your home and describe ho% they are used.
0 0 0
My comp#ter laptop screen My cellphone screen My tele'ision 1ll of those o#tp#t transd#cers listed a2o'e %ork transforming electrical information& electrical domain into non0electrical information& non0electrical domain$ This transformation occ#rs since those de'ice %ork %ith electrical information and %e are a2le to see images on the screen after they con'erts the electrical information into non0electrical information$
,. +o correct #or matrix e##ects the #ollo%in$ procedure %as per#ormed to analye an un'no%n sample #or 9e,; content. +he un'no%n sample %hen analyed by #lame atomic absorption had an absorbance o# .,,. +hen 1. m! o# a standard solution containin$ 1. <$ m!-1 9e,; %as mixed %ith 35. m! o# the un'no%n sample. +he mixture %as then diluted to1. m! in a &olumetric #las'. +he absorbance o# this solution %as .52. What is the ori$inal concentration 4<$ m!-1 o# 9e,; in the un'no%n sample? -
35" 6 +$(7+ <$ m!-1
#
%
8l#s dil#tion factor! +$(7+ $ &++)9: 6 +$9: ;g m< 0 of #nkno%n compo#nd /. = least-s"uares analysis o# calibration data #or the determination o# citric acid in #ruit >uice by *P!C yielded the e"uation: S @.3, 4ccitricacid ; 1@1.@. +he concentration 4m$ ! -1 o# citric acid is denoted as ccitricacid and S represents the area o# the chromato$raphic pea' #or citric acid. 7se the e"uation abo&e and the #ollo%in$ replicate data to calculate the 4a calibration sensiti&ity 4b analytical sensiti&ity and the 4c detection limit. Conc. )# citric Aumber ean Dalue tandard acid o# Beplicates o# S 8e&iation 4m$ !-1 /. 1 ., F 15 ,. F 1/
.
,
#a%
1.30 F 1,
2.2 F 11
