Lab - Iodine Assessment

Question 1

not part of iodine cycle
A.Iodide ions in fresh water are reduced to
elemental iodine
B. elemental iodine volatilizes into the
atmosphere
C. iodine returned to the soil by
rain

Answer 1

A

sea water + oxidized dapat

Question 2

false about urinary iodine concentration
A.More than 90% of dietary iodine absorbed
is excreted in the urine
B. Excellent indicator of recent iodine intake
C. can be measured in spot urine
specimens from a rep sample and expressed
as the mean

Answer 2

C

median, not mean

Question 3

A \_\_\_ value of UIC suggests that a population is
at higher risk of developing thyroid
disorders.
A. lower
B. higher
C. It depends on the age.
D. It depends on the gender.

Answer 3

A

Question 4

___ may be unreliable for estimating

daily iodine excretion from malnourished spot subjects.

Answer 4

Creatinine

Question 5

Daily iodine intake for population

estimates from UI, using ___

Answer 5

estimates of mean 24-h urine

volume

Question 6

When you extrapolate daily iodine intake for popu from UI using est of 24h urine vol, how much bioavailability do you assume iodine has? (average)

Answer 6

92%

Question 7

urinary iodine (μg/liter)
x \_\_\_
body weight (kg) = daily iodine intake

Answer 7

0.0235

Question 8

first step in urine iodine determinaton: Urine is digested with ___under mild conditions

Answer 8

chloric acid

Question 9

second step, UI det: iodine is determined
manually by catalytic role in the reduction
of (A) in the presence of (B)

Find (A) & (B)

Answer 9

(A)ceric ammonium sulfate

(B) arsenious acid.

Question 10

Sandell–Kolthoff reaction: What is it?

Answer 10

iodide catalyzes the reduction of ceric ammonium sulfate (yellow) to the colorless cerous form in the presence of
arsenious acid

Question 11

Sandell–Kolthoff reaction: performed at what radiation wavelength?

Answer 11

405-420 nm

Question 12

serum TSH is determined mainly by the

level of ___

Answer 12

circulating thyroid hormone

Question 13

if the initial blood spot TSH >__ mIU/L, hypothyroidism is possible

Answer 13

20

Question 14

synthesized only in the thyroid and is

the most abundant intrathyroidal protein; increases in amount if the patient has goiter

Answer 14

thyroglobulin

Question 15

requirements of commercial kits that measure TSH: enum

Answer 15

venipuncture
centrifugation
frozen sample transport,

Question 16

serum Tg is normally less than __ıμg/liter

Answer 16

10

Question 17

Which is false?
A. Most iodine that is absorbed is excreted in the urine.
B. Urinary iodine determination is only useful for population-based estimate of iodine deficiency.
C. Late night urine specimens are the best in determining iodine deficiency.

Answer 17

C

early morning dapat

Question 18

In iodine determination, urine is first digested with ___

Answer 18

chloric acid

Question 19

Iodine is determined by catalytic role in what reaction?

Answer 19

reduction of ceric ammonium sulfate in the presence of arsenious acid

Question 20

spectrophotometer setting @ redox reaction that determines iodine

Answer 20

405 nm

Question 21

Enumerate solutions involved in the determination of iodine in urine (manual)

Answer 21

chloric acid solution
5 N H2SO4
arsenious acid soution
ceric ammounium sulfate solution
standard iodine solution

Question 22

These two solutions are substances that have been formed using a process that involves deionized water. Heat therefore is generated in their formation. What are these reagents?

Answer 22

5 N H2SO4

ceric ammounium sulfate solution

Question 23

Which solution must be stored in 4 deg C, for iodine det?

Answer 23

chloric acid solution

Question 24

T/F. For iodine det (manual),the exact time and temperature are not critical as long as all the tubes are heated in the same way.

Answer 24

T

Question 25

In the middle of the procedure for iodine det, some samples may turn into (Color)

Answer 25

faint yellow

Question 26

Which is false about the iodine determination method?
A. The digestion procedure has a set end point.
B. Exact temp, heating time and cooling time vary.
C. The salts generated may be explosive.
D. There may be exposure to perchloric acid fumes.

Answer 26

A

That’s why blanks and standards are important

Question 27

At standard curve for iodine determination

___: X axis
___: Y axis

Answer 27

Iodine concentration of each std: X axis

Question 28

Standard curves for each assay can be prepared by:

__ or individual stock solns of desired iodine conc

Answer 28

fresh each time by appropriate dilutions of 1μg/mL soln of KIO3