Apparatus for Tests and Assays

Note Gelatin capsules may contain significant amounts 

Note Saturation of the liquid with oxygen is essential 

Ignite the fuse-strip by suitable means. If the strip is ignited outside the flask, immediately plunge the sample holder into the flask, invert the flask so that the absorption solution makes a seal around the stopper, and hold the stopper firmly in place. If the ignition is carried out in a closed system, the inversion of the flask may be omitted. After combustion is complete, 

Thermometers suitable for Food Chemicals Codex use conform to the specifications of the American Society for Testing and Materials, ASTM Standards E 1, and are standardized in accordance with ASTM Method E 77. 

The thermometers are of the mercury in glass type, and the column above the liquid is filled with nitrogen. They may be standardized for total immersion or for partial immersion and should be used as near as practicable under the same condition of immersion. 

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Sample Digestion Fortification Preparation Weigh a representative sample on a balance with 0.1-mg precision (see Weights and Balances under Apparatus for Tests and Assays, Appendix I). Transfer the sample to a digestion vessel that has been cleaned according to the manufacturer s specifications. Slowly add 5.0 mL of concentrated nitric acid to the digestion vessel, seal, and heat the vessel for 8 to 16 h at 210° 5°. Allow the vessel to cool to room temperature, and quantitatively transfer its contents into a clean, dry, tared 1-oz polyethylene bottle. Slowly add concentrated hydrochloric acid to achieve a final concentration of 10% (w/w), and dilute to an appropriate final mass with High-Purity Water. 

Anisic Alcohol, 456 Anisic Aldehyde, 524 Anisole, 456, 606 Anisyl Acetate, 456, 568, 606 Anisyl Acetone, 524 Anisyl Alcohol, 456, 606 Anisyl Formate, 456, 607 Annatto Extracts, 31 Anthrone TS, (Sl)114 Antimony Trichloride TS, 850, 851 APDC Extraction Method, 766 APM, 35, (S 1)4 APM-Ace, (S3)5 APO, 32 Apocarotenal, 32 p-Apo-8 -Carotenal, 32 Apparatus for Tests and Assays, 4, 727 D-Araboascorbic Acid, 134 L-Arginine, 32, (S3)5 l-Arginine Monohydrochloride, 33 Arsenic Specification, Requirements for Keeping, xv... 

In addition to the dissolution and identification tests, the ability of the system to perform an assay and a content uniformity determination has been demonstrated. Because there are no fluid transfers, the vessels can be sealed, eliminating the need for volume corrections or fluid replacements. Therefore, with a 12-vessel dissolution apparatus, it is possible to designate 10 of the vessels for the content uniformity test and to average the results from the 10 or 12 vessels for the assay determination. Typical data for a 12-hour controlled-release product are presented in Table 2. Excellent agreement between the fiber-optic- and HPLC-based measurements is evident. 

A variation of the M. C. P. method by Gunter (56) is based on the stringiness of the mucin clot and measures the length to which a filament of the substrate solution can be drawn at a standard velocity. Hyaluronidase destroys the stringiness. Dialyzed synovial fluid is used as the substrate. The method requires, a special apparatus for the determinations. The assay is independent of hydrogen ion concentration between pH values of 6.1 and 7.9. The optimum sodium chloride concentration lies between 0.1 and 0.2 M. A unit is defined as the amount of enzyme which will reduce the stringiness to 50% of the initial value in 20 minutes under the conditions of the experiment. The method appears to be considerably more sensitive than the M. C. P. test. 

Blend Preparation Techniques—Techniques for the preparation and assay verification of calibration blends in the laboratory are described in Appendixes XI and X2. Also, a technique using a moving piston graduated cylinder apparatus, that is described in the calibration section of Test Method D 4468, can be used. However, some laboratories have found that the preparation of such blends is far from easy, and successful efforts require considerable knowledge and experience. 

The in vivo micronucleus test is used for the detection of damage to chromosomes as well as the mitotic apparatus in bone marrow or peripheral blood cells of rodents. The assay system has been well standardized.14-17 The basic features of the test system are (1) the effect of the test chemical is observed in anucleated polychromatic erythrocytes (PCEs) (2) PCEs have a relatively short lifespan, so that any micronuclei they contain must have been generated as a result of recently induced chromosome damage (3) micronuclei are readily identifiable and their distribution is well defined and (4) the frequency of induced micronuclei in PCEs is dependent on sampling times. 

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