LAB 7 - Sodium

Question 1

prior to flame photometry and ion-selective electrodes, the most popular method of determining sodium in body fluids involved its ___

Answer 1

precipitation as the triple salt, sodium uranyl zin acetate

Question 2

the precipitation as the triple salt, sodium uranyl zin acetate for sodium determination is introduced by ___ with subsequent utilization of the precipitate in several ways

Answer 2

kolthoff in 1927

Question 3

one approach for sodium determination is the colorimetric measurement of the solubilized residue itself, either directly, as reported by ___

Answer 3

albanese and lein

Question 4

one approach for sodium determination is by monitoring the color fade of the yellow supernate after precipitation, as described by

Answer 4

bradbury

Question 5

the method presented is essentially adaptation of bradbury’s scheme, wherein __

Answer 5

sodium is precipitated from a protein-free supernate as the triple salt

Question 6

relationship of the absorbance to the sodium concentration

Answer 6

decrease in absorbance (high transmittance) of the supernate-color reagent mixture is proportional to the sodium content of the specimen

Question 7

sodium color reagent

Answer 7

solution of uranyl acetate 5.3 g/dl
zinc acetate 15.4 g/dl

both in aqueous acetic acid-ethanol mixture

Question 8

precipitating reagent for sodium determination

Answer 8

aqueous solution of trichloroacetic acid 10 g/dl

Question 9

sodium standard (140 mmol/L)

Answer 9

sodium chloride 4.091 g/L in aqueous trichloroacetic acid

equivalent to sodium value of 140 mmol/L when used as directed

Question 10

stability of all reagents for sodium determination

Answer 10

15-25*C until expiration labels

Question 11

anticoagulant we can use for sodium determination

Answer 11

lithium heparinate
ammonium heparinate
lithium oxalate

Question 12

urine specimen for sodium determination

Answer 12

24 hr urine specimen

Question 13

ratio of 24 hr urine to distilled water

Answer 13

1:10 (1+9)

depending on sodium content, a dilution of 1:5 or 1:2 may be required

Question 14

sample stability of sodium

Answer 14

sodium levels remain stable for at least 14 days at 15-25*C

Question 15

interfering substances of sodium determination

Answer 15

contaminated glassware - greatest error

Question 16

all glassware must be washed with ____ rinsed thoroughly with distilled water, dried, and stored in dust free area

Answer 16

nitric acid

Question 17

in preparation of protein free supernate

In a properly labelled tubes, we are adding ____ ml of serum, plasma, or diluted urine to each

Answer 17

0.5 ml

Question 18

in preparation of protein free supernate

after adding 0.5 ml of plasma, urine, and serum in each tube, what’s the next step

Answer 18

add 0.5 ml of precipitating reagent dropwise to each tube with vigorous mixing

Question 19

in preparation of protein free supernate

how many mns we need to stand the solution before we centrifuge it

Answer 19

5 mns

Question 20

in preparation of protein free supernate

speed and how many minutes we need to centri the tubes after standing it for 5 mns

Answer 20

5-10 mns high speed

Question 21

in sodium determination, what is the component of a reagent blank

Answer 21

distilled water 0.5 ml
color reagent 2.5 ml

Question 22

in sodium determination, what is the component of a standard cuvette

Answer 22

standard 0.5 ml
color reagent 2.5 ml

Question 23

in sodium determination, what is the component of a sample cuvette

Answer 23

supernate 0.5 ml
color reagent 2.5 ml

Question 24

sodium determination after remixing contents of all tubes, we need to incubate it for how many minutes at what temperature

Answer 24

10 mns at room temperature 15-30*C

Question 25

next step in sodium determination after mixing and incubating it at room temp is what

Answer 25

centrifuging it at high speed for 5 mns

Question 26

we read the sodium at what nm

Answer 26

420 nm, zero the spectro with water.

Question 27

in sodium determination, we must read the blank, standard, unknown within how many minutes

Answer 27

30 mns

Question 28

formula for sodium determination

Answer 28

mmol/L = abs (rb) - abs (U) / abs (rb) - abs (S) X 140

Question 29

equivalent sodium standard value is

Answer 29

140 mmol/L

Question 30

another formula intended for urine sodium

Answer 30

urine sodium (mmol/L) X 24h volume divided by 1000 urine sodium (mmol/L) came from the general formula

Question 31

normal range for serum/plasma sodium

Answer 31

135-155 mmol/L

Question 32

normal range for urine sodium

Answer 32

75-200 mmol/24h