o-Toluidine, 6% (v/v) in glacial acetic acid, is used to determine glucose in biologic material after deproteinization with 3% (w/v) trichloracetic acid. A stable green color develops after heating at 100° for 10 min., and the absorbance is determined at 630 or 635 mµ. The reagent is stable for many months at room temperature, and the reaction follows Beer's Law over a very wide range of concentrations. The development of the procedure is discussed, as is the specificity of the method for glucose.

No abstract

Four methods for blood-alcohol analysis--gas chromatography, enzymatic oxidation with alcohol dehydrogenase, chemical oxidation with acid dichromate, and osmometry--are briefly reviewed from the point of view of the clinical laboratory. Advantages and limitations of these methods are discussed, and their key features are tabulated. The correlation of the results of blood-alcohol analyses with stages of alcoholic influence and their corresponding signs and symptoms is presented in tabular form.

Presently when one uses the terms “breath analysis,” “breath testing,” or even the unqualified “chemical testing,” people, generally, think of a determination of alcohol in a specimen of breath for medicolegal purposes. (The unmodified term “alcohol” in this article refers to ethanol.) This is because of the notoriety of this application and, perhaps, the strong resentment of many to the police procedures involved. Actually, analysis of breath has been undertaken for a variety of purposes since before the recorded history of man. Thus an almost infinite number of conscious judgments about, or unconscious responses to, components of his inspired breath have been made based on odor, taste, and other sensory effects, many of these crucial for well-being or survival of both man and other animals. A striking example is the functioning of pheromones [1].

Sterile whole human blood control materials were commercially prepared in batches containing anticoagulants and preservatives and approximately 90, 150, and 230 mg/dL ethanol with and without 0.3% (w/v) sodium azide. Aliquots in sealed vials were stored by the manufacturer at 2-8 degrees C until shipped monthly to three academic toxicology laboratories that analyzed them in duplicate by gas chromatographic headspace methods at monthly intervals for one year. The resulting data were pooled, and grand mean values were statistically analyzed to determine the respective alcohol stability in these azide-free and azide-containing blood samples. Azide-containing blood samples showed no alcohol losses during the 1-year period. Azide-free blood containing 1.0% (w/v) sodium fluoride and anticoagulants had small alcohol decreases over time, the total losses after one year being less than 5% of the original alcohol concentrations. The initial alcohol concentration of approximately 40 mg/dL also did not change during storage of additional samples of azide-free blood for one month at 4 degrees C. We concluded that addition of sodium azide to performance-test and control blood specimens for alcohol analysis is unnecessary and unwarranted and that alcohol losses in such blood samples can be minimized by simple appropriate treatments and conditions.