ANALYTICAL CHEMISTRY
932 cause single-slit collimators were used, radiation from only a small portion of the sample was measured each time and it was felt that this would afford a good test of homogeneity. Table I shows the individual measurements and the average? for the ratio
MoKa NbKa'
ADVANTAGES OF T H E BRIQUETTINC TECHNIQUE
-Istatistical analysis of the data for the presence of honiogeneity is summarized in Table 11. Table 11.
quets. However, the greatest variation found for two sides of one briquet was 1.3% and this is an acceptable precision for ore and mineral analysis.
The advantages of this briquetting technique are ease of mixing; convenience of handling and storage; nonhygroscopicity of aluminum, .permitting good mixing and making of stable briquets; reproducibility of sample preparation; and simple method for incorporating an internal standard. (The internal standard is easily incorporated into the aluminum powder.)
Summary of Statistical Test for Homogeneity
Briquets Between sides of briquets Between determination on same side
df
.\lean Sgt:ares
F
ACKNOW LEDGM E S T
4
5
0.000673 0.000371'
2 5
40
0,000101
The authors wish to thank IT.J. 'I-ouden and llarvin Zelen, Xational Bureau of Standards, for their aid in the preparation and interpretation of the statistics.
? i
The analysis reveals that determinations from different sides made on the same briquet show less agreement than deterniinations made on a single side and that the briquet averages do not differ as judged by the agreement shown by the two sides of bri-
LITERATURE CITED
(1) Adler, I., and .Ixelrod, J. LI.,J . O p t . Soc. A i w r . , 43,7G9 ( 1 9 S ) .
RECEIVED for review August 25, 1953. lcceyred February 5 , 1954, lication authorized by the Director, C . s;.Geologicai Siin-ey.
Pub-
Determination of Methanol in Biological Fluids by Microdiffusion Analysis MILTON FELDSTEIN and NlELS C. KLENDSHOJ Division of Toxicology, University of Buffalo, School of Medicine and the Biochemistry Laboratory, Buffalo General Hospital, Buffalo, N. Y.
T
HE methods that have been proposed for the detection and estimation of methanol in biological fluids have all been based on an initial distillation to isolate the volatile alcohol (3, 4). This step necessitates the use of special equipment and fairly large samples of biological material, and is thus unrvieldy for routine determinations. In the method described here, the alcohol is separated from the biological material by diffusion in a standard Conway microdiffusion cell (2, 6 ) , thus eliminating the necessity for distillation and permitting the use of small aliquots of material. The methanol is absorbed by a solution of sulfuric acid in the center well of the Conway unit, and then determined quantitatively by oxidation to formaldehyde and subsequent reaction with chromotropic acid (1,8-dihydroxpnaphthalene-3,6-disulfonicacid) ( 1 ). The specificity of the reaction between formaldehyde and chromotropic acid is indicated by the fact that alcohols, ketones, and the following aldehydes do not react to give a colored solution: acetaldehyde, propionaldehpde, butyraldehyde, isobutgraldehyde, isovaleraldehyde, chloral, glyoxal, benzaldehyde, and phthalaldehyde. Glyccraldch) de gives a yellow color ( 1 ). REAGEATS
Sulfuric acid. Dilute 10 ml. of concentrated sulfuric acid to 100 mi. with distilled water. Potassium carbonate, saturated aqueous solution. Chromotropic acid, 0.570 aqueous solution. Prepare fresh weekly and keep under refrigeration. Potassium bisulfite, saturated solution. Potassium permanganate, 5 % aqueous solution. Sulfuric acid, concentrated, reagent grade. White petroleum vaseline lubricant. PROCEDURE
Pipet 2.2 ml. of the 10% sulfuric acid solution into the center well of a Conway unit. I n the outer compartment place a n aliquot of biological material (0.5 ml. of blood or urine). Apply the vaseline lubricant to the surface of the ground-glass cover plate and place on the unit P O that only a small portion of the outer compartment remains unroveietl. .\(Id to the outer compartment
1.0 ml. of the potassium carhonate solution and *ea1 the unit. Carefully tilt the cell several times to allow the fluids in the outer compartment to mix thoroughly. .Illow the cell to stand at room temperature for 2 hours. Pipet 1.0 ml. of the sulfuric acid solution from the center \vel1 into each of two 25-ml. test tubes (19 X 150 nini.). Add to one of the tubes 1 drop of potassium permanganate solution and allon to stand for 5 minutes, mixing occasionally. At the end of this time, add potassium bisulfite dropwise until the excess pernianganate is completely decolorized. T h e second tube serves as a control to detect the presence of formaldehyde and is not treated with permanganate. Prepare a third tube containing 1.0 nil. of distilled water as a blank. To each, add 0.2 ml. of the chromotropic acid solution and place in an ice bath. Add 4.0 ml. of concentrated sulfuric acid to each tube, mix well, and place the tubes in a boiling water bath for 15 minutes. Cool to room temperature, transfer quantitatively to a IO-ml. volumetric flask, and dilute to mark. Cool again, and redilute to the mark. T h e absorbance is then determined in a spectrophotonieter a t a wave length of 580 mp, with the blank set a t zero density. calibration curve is prepared by oxidizing known amounts of methanol in 10% sulfuric acid according to the procedure described above. The Beer-Lambert laws apply over the range of concentration 0.004 t o 0.08 mg. of methanol. This represents a range of concentration in 0.5 ml. of biological sample of 1.8 to 35 mg. %. If the concentration is greater than 35 mg. %, the determination is repeated on 0.5 nil. of a diluted aliquot of biological material. If the concentration is less than 1.8 mg. yo (0.004 mg. methanol in 1 ml. of absorbing solution), the determination is repeated on a larger volume of biological material. However, in this case it is necessary to determine a new correction factor for the diffusion equilibrium as described in the experimental section. I n the absence of formaldehyde-i.e., control tube remains colorless-unknowns are read directly from the calibration curve, and corrected for incomplete diffusion as described below. When small amounts of formaldehyde are present, the ahsorbance of the unoxidized control sample is subtracted from the absorbance of the oxidized sample. If the sample is grosslv contaminated with formaldehyde, the method is not appllcuble. EXPERIMCVT 4 L
Known amounts of methanol were added io I1100d a n d urine samples which weix shown to he free of methanol and were as-
V O L U M E 2 6 , NO. 5, M A Y 1 9 5 4
933 ___-
twhniquc. Recovery of metlianol in the presence of ethyl alcoho1 is shown in Table I. Table I1 shows the methanol content of the blood and urine from cases of methanol poiponing.
Recovery of Methanol from Biological Fluids
Table l.
Alcohol Found Blood
.4lcollol .4dded,
I‘onnd,
Mg.
mg.
0 0100
0 00616 0.0063 0 0062 0 0255b
Recovery,
0.0410
0 0120
0.0800
0 0653h 0 0640 0 0660
62 80 s3
0.0250 0.0230 0 0400b
0 0500
c
96.5 100.0 99.5 103 0 100.0 100.0 97 0 99.5 102.0 99.5 97 0 100.0
0 0062b 0.0064 0.0082 0 0244b 0 0253 0 0250 0 041Ob 0.0400 0.0420 0 065Ob 0.0644 0 0671
r7
hl
-
0 0300
Found,
(-
E.3 h2 55 h3 63 b0 h2 84
Urine
Recovery corrected, n
mg.
Recovery, c/O
62 64 62 61 64 83
62 60 64 81 60 64
Spinal Fluid Recovers Recovery corrected, Found, Recovery, corrected,
sOa
99.5 102.0 99.5 96.5 102.0 100.0 99.5 97.0 102.0 96.5 97.0 102.0
llultiplied by difii;sion comxtion factor 1.21. In rlir j,rect.nce of 1.0 I I I C . of ethyl alcohol. .....
Table 11.
Hecoier?- of Jlethanol i n Cases of I’oisoning Xlg. +‘ ;. rorrected ___
so,
- .>_ -
(40 2
198
-_16 3 .’,le
137’5
,j
20 7 11 6 !i 2 14 6
.4
R thods for ethyl alcohol are rendered more specific. 61
63 62 63
~~~~
3letlranol Found,
C’arr
mg.
0.0084 0.0082 0.0080 0.0246 0.0250 0.0244 0.0425 0.0410 0.0415 0.0650 0.0660 0.0671
~
LITERATURE CITED
(1) Boos, R . S . ,ASIL. CHEL\I., 20, 964 (194s). ( 2 ) Co11wv, E. G., “Microdiffusion -Inalpsis and Volumetric Enor,“ Sen- Tork, D. Van Sostrand Co.. 1950. (3) DenigPs, G., Compf.rend., 150,832 (1910). (4) Gettler, .I.O., J . Riol. Cho,,., 42, 311 (1920). ( 5 ) Punshine, I., a i d S e n a d , R., A s . 4 ~ CHEM., . 25, 653 (1953). RECFITEDf o r rerielv January 28, i 4 3 + . .\crepted LIarch 4, 1954.
Analysis of Mixtures of White Phosphorus, Phosphorus OxychIoride, and Phosphorus T richI oride R. A. KEELER, C. J. ANDERSON, and D. SATRIANA Vitro Corp. o f America,Wert Orange,
T
N. 1.
H E writers encountered a requeat for the analysis of a mixture o f phosphorus compounds-white phosphorus (P), phofiphorus oxychloride (POCI,), and phosphorus trichloride (I’C‘I3), Sfethods are available for determining each compound of the mixture; however, there are no methods for a mixture of these compounds. The mixture is unusual in t h a t it presents an element in three oxidation states. Hydrolysis of the mixture gives a white waxy solid (white phosphorus), phosphorous acid, phosphoric acid, arid hydrochloric acid, according to the folloning equations:
POClr
+
3HzO
+
I-IJ’O,
PCI3 f 3HzO + HIPO,
+ 3HC1 + 3HC1
ill 12)
This ohseri-ation suggested n.aJ.s of separating phospliol UE from the phosphorus ox!-chloi,ide a n d phosphorus trichloride. Filtration was not dcsirahlc because of the spontaneous ComhuEtion of the white phosphorus. -4s all the compounds art. soluhle in hcnsene, the authors decided to t r y a water extraction; however, phosphorus trichloride and phosphorus oxychloride could not be quantitatively hydrolyzed and rxtrarted in this manner.
