Lab - Iodine Assessment Flashcards
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
A
sea water + oxidized dapat
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
C
median, not mean
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.
A
___ may be unreliable for estimating
daily iodine excretion from malnourished spot subjects.
Creatinine
Daily iodine intake for population
estimates from UI, using ___
estimates of mean 24-h urine
volume
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)
92%
urinary iodine (μg/liter) x \_\_\_ body weight (kg) = daily iodine intake
0.0235
first step in urine iodine determinaton: Urine is digested with ___under mild conditions
chloric acid
second step, UI det: iodine is determined
manually by catalytic role in the reduction
of (A) in the presence of (B)
Find (A) & (B)
(A)ceric ammonium sulfate
(B) arsenious acid.
Sandell–Kolthoff reaction: What is it?
iodide catalyzes the reduction of ceric ammonium sulfate (yellow) to the colorless cerous form in the presence of
arsenious acid
Sandell–Kolthoff reaction: performed at what radiation wavelength?
405-420 nm
serum TSH is determined mainly by the
level of ___
circulating thyroid hormone
if the initial blood spot TSH >__ mIU/L, hypothyroidism is possible
20
synthesized only in the thyroid and is
the most abundant intrathyroidal protein; increases in amount if the patient has goiter
thyroglobulin
requirements of commercial kits that measure TSH: enum
venipuncture
centrifugation
frozen sample transport,
serum Tg is normally less than __ıμg/liter
10
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.
C
early morning dapat
In iodine determination, urine is first digested with ___
chloric acid
Iodine is determined by catalytic role in what reaction?
reduction of ceric ammonium sulfate in the presence of arsenious acid
spectrophotometer setting @ redox reaction that determines iodine
405 nm
Enumerate solutions involved in the determination of iodine in urine (manual)
chloric acid solution 5 N H2SO4 arsenious acid soution ceric ammounium sulfate solution standard iodine solution
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?
5 N H2SO4
ceric ammounium sulfate solution
Which solution must be stored in 4 deg C, for iodine det?
chloric acid solution
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.
T
In the middle of the procedure for iodine det, some samples may turn into (Color)
faint yellow
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.
A
That’s why blanks and standards are important
At standard curve for iodine determination
___: X axis
___: Y axis
Iodine concentration of each std: X axis
Standard curves for each assay can be prepared by:
__ or individual stock solns of desired iodine conc
fresh each time by appropriate dilutions of 1μg/mL soln of KIO3
