LAB 8 - CALCIUM Flashcards
a sophisticated and costly way of measuring free calcium is through
ion-selective electrode
a sophisticated and costly way of measuring total calcium is through
atomic absorption spectrophotometry
the most simple and inexpensive method for total calcium assay is based on its direct combination with some reactant, such as _____ to form a STABLE color reaction
ortho-cresolphthalein complexone (OCPC)
the procedure of direct combination with some reactant for calcium determination to form a stable color reaction will eliminates the _____
precipitation of either calcium or protein
the elimination of precipitation of either calcium or protein is required in the early reports of __ and ____ and of ____ and _____
stern and lewis, and of connerty and briggs
the procedure presented in the stan bio is essentially based on the ____ of ____
micromethod of sarker y chauhan
micromethod of sarker y chauhan
where calcium is
___
dissociated from proteins in an acid solution, followed by its direct reaction with OCPC
in a subsequent alkaline medium, the Ca-OCPC complex forms what color complex
purple color complex
the Ca-OCPC complex, purple color, is measured at what nm
550 nm
RS of the color and the amount of calcium in the sample
the amount of calcium in the sample is proportional to the color development in the reaction
the magnesium interference in calcium determination is blocked by
8-hydroxyquinoline and that of heavy metals controlled by potassium cyanide
total calcium color reagent
solution of o-cresolphthalein complexone 0.10 mmol/L
8-hydroxyquinoline 17.2 mmol/L
in dilute hydrocloric acid
total calcium base reagent
solution of 2 amino 2 methyl 1 propanol 970 mmol/L in aqueous potassium cyanide solution
total calcium standard value
10 mg/dl
steps in reagent preparation
equal volume of color and base reagents may be mixed to make a working reagent
allow the working reagent to stand at room temperature for at least 15 mns before use
how many mns we need to stand the working reagent before use
15 mns at room temperature
the working reagent is stable up to
7 days when stored at room temperature 15-30C or
14 days when refrigerated 2-8C
reagent storage and stability for color and base reagents
2-8*C until expiration date
reagent storage and stability for calcium standards
15-25*C until expiration date
spectrophotometer absorbance reading for calcium
550 nm
specimen of choice for calcium determination
serum
anticoagulant for plasma
heparin
in calcium determination, after blood collection, we must separate the serum from clot or the plasma from cells within ___
2 hrs
urine (24 hr collection) should be maintained at what ph to prevent precipitation
acid pH
in urine collection, we must use ___ in collection vessel
10 ml of 6M HCL
Precipitated calcium salts in alkaline
urine may be redissolved by acidification of a well-mixed aliquot to pH 1 with concentrated ____.
HCl
what to do to specimens showing a precipitate
discard, as calcium may have combined with fatty acids or proteins
contaminated glassware must be washed with ____
20% nitric acid rinsed well with distilled or deionized water, dried, and stored in a dust free area
anticoagulants to be avoided
oxalates, edta, etc
Abnormally high bilirubin or hemoglobin levels can yield falsely _____ calcium values
low
component of the reagent blank tube for calcium det
color reagent 0.5 ml
base reagent 0.5 ml
component of the standard tube for calcium det
standard 0.01 ml
color reagent 0.5 ml
base reagent 0.5 ml
component of the unknown tube for calcium det
specimen 0.01 ml
color reagent 0.5 ml
base reagent 0.5 ml
we must read the sample in 550 nm for how many mns
within 60 mns
urine samples giving absorbance values which exceed the linearity(15 mg/dl ) should be diluted for what ratio
3 fold 1:3
1 parts urine
2 parts distilled water
serum or urine calcium formula
au/as X 10
urine calcium another formula
urine calcium (mg/dl) X F X volume for 24 hr
divide them all by 100
ref range for serum calcium
9.2 - 11 mg/dl
ref range for urine calcium
100-240 mg/24hrs
