MIL-DTL-10958G
Xylenol orange reagent. Dissolve 1.00 gram of xylenol orange in anhydrous methanol and
dilute to one liter with methanol.
4. Apparatus:
Beakers, 250-ml.
Buchner Funnel, 9 cm.
Filtering apparatus, bell-jar type.
Steam bath.
Hot plate
Volumetric flasks, 50-ml and 250-ml.
Pipets, various sizes.
Spectrophotometer, Beckman Model B or equivalent.
Absorption cells, Corex, 4.00-cm light path.
Filter paper, 9 cm Whatman No. 3 or equivalent.
Filtering crucible, 30-ml, fine porosity.
5. Preparation of standard curve:
a. Add 4.0 ml of 5N hydrochloric acid, 5.0 ml of 10% hydroxylamine hydrochloride, 5.0 ml of
zirconium standard solution B and 4.0 ml of xylenol orange reagent to each of six 50-ml
volumetric flasks. Prepare a color blank containing all reagents except the zirconium. Dilute 34
ml of the calcium EDTA standard solution B to 500 ml with distilled water. Pipet into the
previously prepared standard (equivalent to 0, 17, 34, 51, 68, and 85 micrograms of calcium
EDTA), dilute to volume and mix well.
b. Allow the standards to stand for 15 minutes for full color development. Zero the
spectrophotometer on the color blank and read the absorbances of the standards at 535
millimicrons and a cell length of 4.0 cm.
c. Plot the absorbance against the micrograms of calcium EDTA on ordinary coordinate paper.
6. Preparation of samples:
To insure homogeneity of samples, each sample of product under test should be transferred
completely to a Waring blender and blended until no visible evidence of segregation exists.
With products consisting of an oil and water mixture, sampling should be performed while the
sample is still being stirred in the blending step. Exercise caution so that the pipet does not
contact the rotating blades. After blending, unknowns are determined as given below in section
7 (sample recovery curve). Necessary corrections for a given food product blank are made (see
section 10).
11
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business