However, the prospective user, by inspection of the data, can decide the probable accuracy he could obtain. EXPLANATION OF FORM
TITLEIKFORMATIOK;. This is a brief statement of the component(s) of the mixture for which analysis is desired. COMPONENTS.The components are listed in accordance with the International Union rules for naming of organic compounds. EMPIRICAL FORMULA. Given for ease of subsequent indexing. CONCENTRATION R ~ N G EGiven . for component likely to be present. ACCURACY.The values depend on the purity of the reference material. I n some cases, the accuracies obtained may not appear good, but are quite sufficient for the particular problem involved. Therefore, the author uses a conservative limit value; Le., if he reports a concentration of 22% and he estimates the value to lie between 21% and 23%, his accuracy figurp is 1.0%. X or v-B.L. POINTS.The analytical wave lengths or wave number values (A or v) are given as accurately as possible. The base line (B.L.) points are also given below the X or v value if the base line is determined by a line connecting two abscissa values. If it is drawn tangent to an arbitrary spectral slope, the fact should be noted under Comments. SLIT-WIDTH-~IECHANIGAL (mi.) AND SPECTRAL (AX or Av). The mechanical slit-width is given in millimeters and
the spectral slit-width under it in AA or Av since spectral slit-width for a given mechanical slit-width varies with instruments of different manufacture. I n order that the data he consistent, the spectral slit-width is calculated as the sum of the dispersion term and one half the Rayleigh diffraction term.
+
‘,‘2
AXR,,
x 3f
‘1’2
A v R ~ ~
DX X S
Ah =
or AV = DV
where DX or D V is the dispersion in wave length or wave number per millimeter a t the exit slit, S the width of the exit slit in mm and A X R ~or~ AvR,, is the Rayleigh term. Data for D x , Dv, A A R ~and ~ ~ A v R ~ are , given by the manufacturer. Data are consistent in X or v, but not both. Reviewers have data on standard commercial instruments to calculate spectral slit widths from mechanical slit values. COXCENTRATION-LENGTH. The concentration of the analyzed sample and the cell length are given for each point. If these data are constant, they are stated once and dittoed thereaftcr. IXSTRUXICST. The make and model number of the instrument is stated together with the prism material used. SAMPLEPHASE.This describes saniple conditions-Le., solution, gas dilution, liquid, potassium bromide disk, etc. ABSORBAWE MEASUREMENTASD CALCCLATIOX.The most common methods are shown to be checked. The following references are given for the terms used:
Point Method-Vapor Phase. R. R. Brattain, R. S. Rasmussen, and A. hl. Cravath, J. A p p l . Phys. 14,418 (1943). Point ;Method-Liquid Phase. J. R. Nielsen and D. C. Smith, IND.ENG. CHEM., ANAL. ED. 15, 609 (1943); J. IT. Kent and J. Y. Beach, AXAL. CHEJI. 19, 290 (194i). Base-Line Method N. T r i g h t , IND. EXG. CHEJI., ANAL. ED. 13, 1 (1941); J. J. Heigl, ?VI. F. Bell, and J. U. White, AKAL. CHEW 19, 293 (194i); R. A. Friedel and L. Pierce, ANAL. CHEM.22, 418 (1950) ~BSORPTIVITIES-L4NaLPTICAL 11.4T R I X . iibsorptivities are the values of
the slopes of the Beer’s law concentration curves used. If the Beer’s lan line is sufficiently curved that a correction term is applied to use the straight line value, those matrix terms where correction must be applied are underlined. ~IATERIAL PURITY. The probahlc purity of the reference material and the source, if conimercially available, are stated. If materials were not pure, hut absorptivity corrections for impurities were made, this should be stated. COM\IENTS. Comments cover any unusual points such as shutter zero niaterials, special sampling precautions, special treatment of Io reference signal, calculation of absorbance, methods that are not standard, etc. Wherever possible, a literature reference when applicable is preferred to an explanation. Comments are as brief as possible. If too much comment is necessary, probably a full paper or an Inalytical Kote is adrisable.
Determination of Phenol, o-tert-Butyl Phenol, p-terf-Butyl Phenol, 2,CDi-tert-Bu t y I Phenol, and 2,4,6-Tri-terf-Butyl Phenol in tert-Butyl Phenol Mixtures R . 1. SCHEDDEL and L. R. KILEY, The Dow Chemical Co., Midland, Mich.
cs- 1 Cell Windows: NaCl Absorbance Meosuremenf:
I
Component Name
No
-
1.
~
Formula
_
_
%
~
%
_
Base-Line--
C U J C U ~ O J ~Inverted O~; Matrix-X
Pts.
_
Point-X Successive Approx..-
--
Graphical--
Phenol Relative Absorbancesn-AnaJyticol
phenol
Componenf/X
14.5
9.5
9.0
9.2
13.0
1.
1.756 0.075 0.073 0.024 0.026
0.137 0.601 0.051 0.064 0.025
0.162 0.145 0.620 0.120 0.143
0.136 0.893 0.076 1.182 0.064
0.321 0.137 0.041 0.019 0.333
2.
3.
-
Mofrix:
4. 5. ~
,
butyl phenol
Instrument: Perkin-Elmer Model 12, NoCl prism Sample Phase: Solution in carbon disulfide
1552
ANALYTICAL CHEMISTRY
Maferiol Purify: Reference compounds 99%, pure or better Commenfs: Samples must b e melted and thoroughly mixed before preparing solutions. Relative absorbances are given as the slope of the Beer’s law concentration curves used expressed in terms of absorbance per 100% of constituent.
