An Application of 

Spectrographic 

Microphotometric 

Scanning 

GEOLOGICAL SURVEY BULLETIN 1036-E 

This report concerns work done on 

behalf of the U. S. Atomic Energy 

Commission and is published with 

the permission of the Commission 
An Application of 

Spectrographic 

Microphotometric 

Scanning 

By C. L. WARING, MONA FRANCK, and A.M. SHERWOOD 

A CONTRIBUTION TO GEOCHEMISTRY 

GEOLOGICAL SURVEY BULLETIN 1036-E 

This report concerns work done on 

behalf of the U. S. Atomic Energy 

Commission and is published with 

the permtssion of the Commission 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1956 
UNITED STATES DEPARTMENT OF THE INTERIOR 

Douglas McKay, Secretary 

GEOLOGICAL SURVEY 

W. E. Wrather, Director 

For sale by the Superintendent of Documents, U. S. Government Printing Office 

Washington 25, D. C.. - Price 15 cents 
CONTENTS 

Page 

Abstract---------------------------------------------------------- 69 

Introduction and acknowledgments_--------------_._ ________ ------___ 69 

Experimental data and ____________________________________ ~-_______ 70 

Preparation of standards_______________________________________ 70 

Procedure---------------------------------------------------- 71 

I>iscussion________________________________________________________ 72 

References cited___________________________________________________ 73 

TABLES 

TABLE 1. Example of scanning information for aluminum, recorded on card__________________________________________________ 74 

2. Spectrum lines used and comparison of spectrographic and 

chemical analyses of ashes_______________________________ 75 

3. Standard sensitivities for the elements determi:r;ted by the microphotometric method____________________________________ 79 

4. Summary of lines used, percentage range, and rating of line in 

spectrographic analvsis of ashes__________________________ 79 

m 
A CONTRIBUTION TO GEOCHEMISTRY 

AN APPLICATION OF SPECTROGRAPHIC MICROPHOTO· 

METRIC SCANNING 

By C. L. WARING, MoNA FRANCK, an~ A. M. SHERWOOD 

ABSTRACT 

A previously published semiquantitative spectrographic method was modified 

by applying microphotometric scanning of the spectrograms in such a way 

that the operator was free to do other work during a large part of the scanning 

time. The spectrograms of 5 ash samples from Dakota lignite and one synthetic 

mixture were scanned for 68 elements; 32 elements were found and those below 

10 percent were reported quantitatively. 

The tests included a spectrum-line study to provide lines least enhanced or 

depressed by matrix differences, information on accuracy, on human error, and 

eye fatigue. 

In 93 percent of the cases the agreement with the chemical analysis was within 

a factor-of-10 bracket, 85 percent were within a factor-of-5 bracket, and 79 percent were within a factor-of-2 bracket. 

INTRODUCTION AND ACKNOWLEDGMENTS 

In a semiquantitative spectrographic method for the analysis of 

minerals, rocks, and ores, described by Waring and Ann ell (1953), 

the procedure included the analysis of an unknown for 68 elements in 

one exposure of a 10-mg sample. The final results were obtained by 

visually comparing spectral lines of the unknown with the same lines 

on standard plates. 

The present study is a modification of the semiquantitative method 

to ·include the application of microphotometry to the spectrograms. 

An increase in the accuracy and precision of the results would make 

the data obtained more applicable to the geochemical problems being 

studied. The experiments were conducted with the expectation of 

applying the procedure to numerous types of samples and reporting 

the results quantitatively or in narrow concentration ranges. 

The spectrograms were scanned and recorded automatically on a 

commercial microphotometer. The procedure permitted the operator 

to do other work during a large part of the scanning time, after adjusting the sensitivity of the instrument. Working with an enlarged 

chart (lOX) was less fatiguing for the operator than using the mag365773-56 69 
70 CONTRIBUTIONS TO GEOCHEMISTRY 

nifying glass for plate interpretation. However, because 68 elementS'. 

(table 3) are being determined spectrographically at the present time,. 

photographic plates are still being used in most of our analytical 

work. Determining this large number of elements in rock samples that. 

exhibit nonuniform burning characteristics is still difficult with avail-· 

able commercial direct-reading instruments. A permanent record of 

the spectrograms has definite reference value in the laboratory. We 

plan to determine the adaptability of the method with the instruments 

in the laboratory before attempting the direct reading approach. 

The method was applied to the ash of five Dakota lignite augerhole samples and one synthetic mixture. Because many semiquantitative analyses of the ashes of low-rank coals ~re performed in 

our laboratory in connection with the geochemical studies of lignites, 

any improvement in the method could readily be applied to the lignite 

problem. The major components of the lignite ashes (usually consisting of iron, silicon, aluminum, sodium, and calcium) may vary 

considerably from sample to sample. Selection of these samples would 

fit into our plan of studying numerous lines and selecting those least 

enhanc~d or depressed by matrix differences. 

The percentage composition of the synthetic sample was as follows: 

aluminum, 13; silicon, 11; iron, 8.75; sodium, 2.5; calcium, 8.08; 

magnesium, 1.5; potassium, 2; uranium, 1; titanium, arsenic, boron, 

barium, phosphorus, thorium, each 0.5; strontium, cobalt, manganese, 

nickel, lead, chromium, zirconium, zinc, cerium, copper, each 0.05; 

yttrium, molybdenum, germanium, gallium, ~in, vanadiQm, scandium, 

lanthanum, each 0.005; and silver and ytterbi~m, each 0_.0005. 

A survey of the literature reveals that several similar '·methods 

(Eeckhout, 1945, and Meggers, 1950) are being applied in other 

laboratories on different materials with different standardization procedures and visual estimation of results. 

Thanks are expressed to members of the Geological Survey who 

have aided in this investigation-especially to Helen Worthing and 

C. S. Ann ell who made many of the determinations and to F. S. 

Grimaldi who supervised the chemical analyses. This work is part 

of a program being conducted by the Geological Survey on behalf of 

the Division of Raw Materials of the U.S. Atomic Energy Commission. 

EXPERIMENTAL DATA 

PREPARATION OF STANDARDS 

As in the procedure described previously (Waring and Ann ell, 1953), 

the standard solutions were made to contain 10 mg of the element per 

milliliter of solution. These solutions were diluted until 0.1 ml of 

each equals 10, 1, 0.1, 0.01, 0.001, and 0.0001 percent based on a 10-mg 

sample of the unknowns. A 0.1-ml aliquot of the solution was then 
SPECTROGRAPIDC MICROPHOTOMETRIC SCANNING 71 

added from a micropipette to the sealed electrode cup. This was 

dried on an asbestos-covered hot plate at a temperature of approximately 100° C. A few milligrams of pure graphite were added to the 

remaining salts in the electrodes. Duplicate sets of electrodes were 

prepared, one set was arced (250 v, 12 amp, d-e) for 60 seconds and 

one for 120 seconds. 

The spectrograms were scanned on a recording microphotometer. 

Data provided by the tracings, including wave length, percent transmittance, and width were recorded on cards as shown in table 1. 

Information on numerous lines was recorded and used in the search 

for lines least enhanced or depressed by the different elements present. 

Selected lines are listed in table 2. 

PROCEDURE 

A synthetic sample of known composition was analyzed with the 

unknowns. The synthetic sample was prepared by adding standard 

solutions of the minor elements to the oxides of the major components (table 3). After drying on a hot plate, the material was ignited 

at 500° 0 for four hours. The synthetic sample was ground in a boron 

carbide mortar to pass a 100-mesh stainless-steel screen and thor- . 

oughly mixed by passing repeatedly through an 80-mesh stainlesssteel screen. 

A 10-mg sample of lignite ash obtained according to the method 

of Fieldner and Selvig (1951) was weighed, mixed thoroughly with 

two parts by weight of pure graphite in the weighing pan, and placed 

in the electrode cup through a polished stainless-steel funnel. The 

unknowns were arced (250 v, 12 amp, d-e) for either 60 or 120 seconds, 

depending on the behavior of the sample in the arc or on past experience with the type of material. Experience has shown that the 

error is not great if the sample is arced for 60 seconds instead of 120 

seconds. 

After the plates were processed, the spectrograms were scanned 

with a recording microphotometer. The proper lines were located 

on the scannings and the height and, if necessary, the width determined. 

The concentrations of the elements were interpolated by direct 

proportion from the data on transmission versus percent concentration. Information on the previously prepared cards (table 1) obtained from the standard plates was used in the interpolations. The 

precision and type of data sought did not warrant the use of the more 

precise logarithmic function-emulsion calibration method, especially 

in view of the other sources of error. 

As previously described (Waring and Ann ell, 1953), on each plate, 

along with the spectra of the unknowns, were recorded spectra of 
72 CONTRIBUTIONS TO GEOCHEMISTRY 

iron and of aluminum alloy (Aluminum Company of America standard SA 874). These latter spectra furnish reference points for locating lines and a general index of exposure, of plate sensitivity, and 

of development. 

T4e measured transmission of the chromium line 2780.7 A in the 

spectrum of the aluminum alloy (0.15 percent chromium) is used as 

a rough check on the plate sensitivity and other variables. The 

normal percent-transmittance value of the chromium line is 65 per:-

cent. When the percent transmittance of this line is below 60 percent 

or above 70 percent, the known variables such as temperature of 

development tank, age of developer, voltage and current of the 

source, electrode tips, and wall thickness of the lower electrodes are 

investigated. If these variables are found to be in order, the amount 

of light entering the spectrograph is readjusted with the aid of neutral 

filters to correct for the intensity drift. 

DISCUSSION 

The semiquantitative method has been applied to numerous types 

of materials, and the results were reported in factor-of-10 brackets. 

Experience with the method showed that the standardization, sample 

handling, method of arcing, and development of the plates were satisfactory. The weakest link was the visual plate reading. Microphotometric scanning showed that in 93 percent of the experiments 

the agreement with the chemical analysis was within a factor-of-10 

bracket, 85 percent were within a factor-of-5 bracket, and 79 percent 

were within a factor-of-2 bracket. The precision gained by the 

introduction of microphotometry, as indicated by the tests, warrants 

reporting the values in brackets of smaller concentration ranges than 

for the. previously reported semiquantitative method, with only a 

slight increase in total analysis time. 

A detailed discussion on the observations of individual lines is 

given in table 2. Table 4lists the authors' opinion of the value of the 

selected lines. The results obtained with the lines marked "good" 

generally fall within a factor-of-2 bracket of the chemical analysis, 

and the lines marked "fair" fall within a factor-of-5 bracket. The 

lines marked "poor" are considered undesirable for accurate testing 

by this method unless the results are to be reported in factor-of-10 

brackets. The line magnesium 2781.4 A, sample F84, table 2, illustrates this point; the chemical value was 0.126 and the spectrographic 

value was 0.58 percent, both results falling within a factor-of-10 

bracket. 

The time required for ari analysis is greatly influenced by the skill 

of the analyst and especially the physical nature of the sample to be 
SPECTROGRAPHIC MICROPHOTOMETRIC SCANNING 73 

analyzed. An approximate breakdown of the analysis time is as 

follows: 

Number of samples (952 elements)_:... _____ .;. ________ _: ____ 14. 

Quarter, weigh samples and proper reference samples _____ 4 hours. 

Exposure___________________________________________ 1.5 hours. 

Development ________________________________________ 0. 75 hour. 

Plate scanning and estimates __________________________ 15 to 20 hours. 

REFERENCES CITED 

Eeckout, J., 1945, Algemeene Methode voor de Semi-kwantitatieve Spektraalanalyse van Vaste Stoffen: K. Vlaamsche Wetensch. Belgie, Kl. Wetensch. 

Verh., Jaarg. 7, no. 13, 71 p. 

Fieldner, A. C., and Selvig, W. A., 1951, Methods of analyzing coal and coke: 

U.S. Bur. Mines Bull. 492. 

Meggers, W. F., 1950, Emission spectroscopy: Anal. Chemistry, v. 22, p. 18-23. 

Waring, C. L., and Annell, C. S., 1953, Semiquantitative spectrogr~phic method 

for analysis of minerals, rocks, and ores: Anal. Chemistry, v. 25, p. 1174-1179. 
Line (angstrom) 

TABLE l.:._Example of scanning information, for aluminum, recorded On card 

Transmission 

10 

Line 

width 

(inm) 1 

Percent transmission and width of line, at concentrations indicated in percent 

Transmission 

1.0 

Line 

width 

(rom) 

Transmission 

0.1 

Line 

width 

(rom) 

0.01 

Transmission 

Line 

width 

(rom) 

0.001 

Transmission 

Line 

width 

(rom) 

0.0001 

Transmission 

Line 

width 

(rom) -------------------1 , ____ , ____ , ____ , _____ , ____ , ____ , ____ , ____ , ____ , _____ , ___ _ 

2568.0 .. ---------..•........•.... ----.-----------

2575.1 .. -···· .. ----------------------------·-----

2652.5.------------------------·-----------------

2660.4 .. -----------------------------------------

3082.2.------------------------------------------

3092.7-- ------------------·"---------------------

3059.9.--------------------------------------·---

3064.3.------------------------------------------

3066.2.------·-----------------------------------

11.5 

8 I 14.5 

10 

9.5 

10 

47 m I 45.5 . 

N 

N 

N 

2 

21 

12.5 

24 

16.5 

5.5 

6 

95 

87 

88.5 

N 

. 1 

N 

N 

N 

N 

V2 

79.5 

11.5 

4 

1 Where the width of line was not normal (N), the width was measured nt middle line (50) on chart. 

2 Just visible. · 

N 

N 

1.5 

48.5 

26.5 

N 76 

55 

N 

N 

89 

74.5 

N 

N 

~ 

c 

~ ~ 1-1 

t:l:l 

q 

1-3 

1-1 

~ Ul 

1-3 

0 

0 

M 

0 

a 

::0 

t"'J 

~ U1 

~ 

~ 

~ 
SPECTROGRAPHIC MICROPHOTOMETRIC SCANNING 7 5 

TABLE 2.-Spectrum lines used and comparison of spectrographic and chemical 

analyses of ashes 

Spectrographic 

Line Chern- True 

Ele- (aug- Sample Micro- leal value Remarks mont strom) photo- Visual (per- (permetric (percent) cent) cent) 

scannin~ (percent 

Ag ___ 3280.7 Synthetic. __ 0.00068 0. 0001~. 001 0.0005 Line 3280 A satisfactory when 

background permits its use. 

AL •. 2652.5 Synthetic. __ 10+ 10+ 13. High iron content may interfere 

3059.9 Cl8b ______ 7.1 1.Q-10.0 6. 75 with 3059 A. 

a059. 9 F84. _ ----- 10+ 1.Q-10.0 10.1 

2575.1 F95 _______ 10+ 1.Q-10.0 11.6 

ao59. 9 S29__ ______ 10+ 1. Q-10. 0 9.a 

a059. 9 seas__ ____ 10+ 1.Q-10.0 7.8 

As ___ 2860.5 Synthetic. __ 0.94 0.1-1. 0 0.5 High result is probably due to 

interference by iron. 

B ____ 2497.8 Synthetic. __ 0.4 0.1-1. 0 0.5 Line 2496.7 A may also be used 

C18b ______ 0.022 0. 01-0.1 when the boron is more tharu 

F84------- 0.071 0.01~.1 0.1 percent. F95 _______ 0.066 0.01~.1 S29 ________ 0.08 0.01~.1 

seas ______ 0.07 0.01~.1 

Ba ___ 2aas.a Synthetic •• _ 0.6 -------------- .................... 0.5 Line 23a5 A was satisfactory in 

C18b ______ o.a2 ................................... 0.27 this range. F84 _______ 0.69 0.01~.1 

F95 _______ 0.65 0.01-().1 S29__ ______ 0.26 0.01~.1 

seas__ ____ 0.57 0.01~.1 

Be •.• 2a48.6 Synthetic .•• ---------- .................................. -------- ..................... Be L1ne 2348.6 A satisfactory for 

C18b.----- 0.001a 0. 0001~. 001 -------- low Be content when iron conF84 ....... o.ooa7 0.001~.01 -------- tent is not too high. 

F95. ------ ---------- -------------- -------- S2!L ...... O.OOOla 0. 0001~. 001 seas__ ____ 0.004 0.001~.01 -------- Ca ... aooo. 9 Synthetic ___ 9.2 1.Q-10.0 -------- 8.08 High iron content interferes with 

aoo9.2 -------------- 9.a -------------- -----·-- Ca aooo and aoo9 A lines. The 

3000.9 Cl8b ______ 10+ 1. Q-10.0 11.1 better line seems to be 2997 A. 

aoo9. 2 -------------- 10+ ................................. -------- 2997.a F84 .•• c ••• 4. 75 1.Q-10.0 2.9 

aooo.9 -------------- 7. 78 ................................. -------- aoo9. 2 ................................. 7.66 -------------- ...................... 

2997.a F95. _ ----- 6.00 1. Q-10. 0 7.8 

2997.a S29 ________ 8.07 1.Q-10. 0 8.6 

2997.a seas__ ____ 9.4 ·------------- 14.4 

aooo. 9 ................................ 10+ 1. Q-10. 0 -------- a009.2 -------------- 10+ -------------- -------- Co ___ a45a. 5 Synthetic ... 0.054 0.01~.1 0.05 Background interference appar- F95 _______ 0.05 0.1-1.0 0.04 ently is not too serious. 

Or ___ 28a5. 6 Synthetic. __ 0.04a 0.01~.1 0.05 Line 28a5 A is satisfactory. C18b ________ 0.07 0.001~.01 

F84 _________ 0.01 0.001~.01 

F95. _ ------- ....................... -------------- -------- S29 ____ ------ 0.01 0.001-Q.01 seas__ ______ <o.o1 0. 001-0.01 

Cu.-- a247. 6 Synthetic. __ 0.0088 0.001~.01 0.005 Lines a247 and a274 A are satis· 

a274.0 -------------- 0.0089 factory when Iron content ls not 

a247.6 Cl8b ________ 0.1 0.001~.01 too high. The line width rae- F84 _________ ---------- -------------- -------- tor is difficult to apply when. 

a274. 0 F95 _________ 0.0074 0. 001-Q. 01 copper content is high. 

a247. 6 S29 __________ 0.008 0. 001~-01 

a274. 0 seas__ ______ 0.009a 0.001~.01 
76 CONTRIBUTIONS TO GEOCHEMISTRY 

TABLE 2.-Spectrum lines used and comparison of spectographic and ·chemical 

analyses of ashes-Continued 

Spectrographic 

Line Ele- (angment strom) 

Fe .•• 2936.9 

2953.9 

2936.9 

2953.9 

2599.4 

2599.6 

2936.9 

3008.1 

2599.4 

2953.9 

2936.9 

Ga .•. 2943.7 

Sample 

Synthetic .• _ 

-------------- C18b ______ 

-------------- F84 .• -----

-------------- F95 .••.•.. S29 ________ 

-------------- SC35 ______ 

--------------

Synthetic ... 

C18b ______ 

F84 .. _____ 

F95 _______ 

S29 ________ 

SC35 .. ---~ 

Microphotometric 

scanning 

(percent) 

6. 5 

7.0 

10+ 

----------

10+ 

10+ 

10+ 

10+ 

10+ 

10+ 

10+ 

0.03 

0.04 

0.07 

0.30 

0.35 

0.35 

Oe... 3039.1 Synthetic.__ 0. 0075 

· K____ 3446.4 Synthetic.__ 2. 35 

C18b______ 1. 

F84_______ 2.2 

Mg._ 2778.3 

2778.a 

2779.9 

2778.a 

2779.9 

2781.4 

2778.a 

2779.9 

2781.4 

2779.9 

2798.0 

2779.9 

Mn •• 259a. 7 

2605.7 

2605.7 

2576.1· 

259a. 7 

2605.7 

259a. 7 

2605.7 

2801.1 

259a. 7 

2605.7 

259a. 7 

2605.7 

2801.1 

F95 .• _____ 0.48 

S29 ... _____ 3. 2 

SC35._____ a. 2 

Synthetic... 1. 

C18b. _____ ----------

----------- 0. 9 

F84_______ 0. 764 

----------- 0. 37 

----------- 0. 58 

F95 .. _____ 0.92a 

1. 0 

----------- 2. 6 

S29-------- 0. 78 

seas _____ _ 

Synthetic •.• 

0.155 

0. 78 

0.935 

0.5 

0.062 

0.056 

C18b._____ 0.01 

F84 .. ____ _ 

F95 .. ____ _ 

0.05 

0.092 

0.088 

0.68 

0. 7 

0.1 

S29________ 0.066 

----------- 0. 062 seas______ 0.18 

----------- 0. 089 

0. a25 

Visual 

(percent) 

1.(}-10.0 

-------------- 1. Q--10. 0 

----·--------- 10+ 

10+ 

10+ 

10+ 

10+ 

10+ 

10+ 

0. 001-Q.01 

0. 001-Q.Ol 

0. 001-0-Q1 

0. 01-Q.1 

0.01-Q.1 

0.01-Q.1 

0. 001-Q.01 

1. 0-10.0 

0.1-1. 0 

1. Q--10. 0 

0.1-1. 0 

l.Q--10.0 

l.Q--10.0 

l.Q--10.0 

1. Q--10. 0 

Chemical 

(percent) 

--------

8.0 

--------

24; ' 

21.9 

24.0 

24.0 

15.8 

0. 780 

0.68 

0.68 

1.28 

0.92 

4.4 

0.1-1. 0 0.126 

0. 1-1. 0 0. 1a 

0.1-1. 0 0.138 

0.1-1. 0 0. 072 

0. 01-0.1 

0.04 

0.01-0.1 

0.2 

0.01-0.1 

-------------- o. 78 

0.1-1. 0 

0.11 

0.01-0.1 

-------------- o. 2 

True 

value 

(percent) 

8. 75 

.0.005 

2.0 

1.5 

0 0.05 

Remarks 

Lines 2936 and 2953 A seem best 

in this :ange. 

As a result of previous work the 

visual Ga estimates were downgraded one bracket. This 

work is in agreement. 'l.'he 

reason for this enhancement Is 

unknown. 

Line 3039 A satisfactory at this 

range. Oe not detected in 

other samples. 

Background corrections appar· 

ently are necessary for certain 

samples. 

More work necessary to select 

the better lines for magnesium 

determinations. Line 2779 A 

is best in 0.1-1.0 percent range. 

Lines 2781 and 2778 A are best 

for the l.Q--10.0 percent range. 

Line 2801 A satisfactory only 

_when AI content is very low. 

When AI content is high 2576 A 

Is suggested. Lines 259a and 

2605 A are reliable. 
SPECTROGRAPHIC MICROPHOTOMETRIC SCANNING 77 

TABLE 2.-Spectrum lines used and comparison of speCtographic and chemical 

analyses of ashes-Continued 

Spectrographic 

Line Chern- True Ele- (ang- Sample Micro- teal value Remarks mont photo- (per- (per- strom) metric Visual cent) cent) 

scannin~ (percent) 

(percent 

--

Mo •• 3170.4 Synthetic. __ 0.004 0.001-Q.01 -------- o.oos Use width of 3170 A line for high 

31a2.6 C18b ______ 0.046 0. 01-Q.1 -------- Mo. Line a170 A satisfactory 

3170.4 F84 _______ .............................. 0.1-1. 0 -------- for 0.01-o.1 range. Indications 

3122.0 ----------- 0.24 0.1-1.0 -------- are that a122 A should be used 

3170.4 F9S _______ 0.041 0.01-Q.1 ................... above 0.1 percent. 

3122.0 S29 ________ 0.1 0.1-1. 0 0.1S 

3170.4 ----------- 0.1 0.1-1. 0 -------- 3122.0 seas ______ 0.2 0.1-1.0 -------- Na ___ 3302.3 Synthetic ___ 3. 7 1.Q-10.0 -------- 2.S Both lines in doublet are sattsaao2. 3 C18b ______ 10.-!;: 10.+ 17. factory. 

3302.3 F84------- 4.1S 1. Q-10. 0 2.6 

aao2. 9 F95 _______ 0.98 l.Q-10.0 1. 41 

3302.9 S29 ________ 2.8S 1. Q-10.0 a.26 

aao2. 9 seas ______ 3. 7 l.Q-10.0 2.a3 

NL. 3a93.0 Synthetic. __ 0.3 ................................. -------- o.s Slightly high results are probably 

3423.7 ---·---------- 0.1 0.01-Q.1 -------- due to background. 

3414.8 C18b ______ 0.026 0.01-Q.1 -------- p ____ 253S. 6 Synthetic. __ 0.25 0.01-Q.1 -------- o.s Beware of iron interference. 

Pb ___ 28a3.1 Synthetic. __ 0.68 0.01-Q.l -------- 0. s Previous work indicated that 

C18b .• ---- 0.04 <0.01-Q.1 -------- lead in the low percentages was 

F84.- ----- 0.043 <o.01-o.1 -------- enhanced by one bracket, 

F9S------- 0.059 <O.Ol-Q.1 ..................... Visual results were downS29 ________ 0.057 <0.01-Q.1 ...................... graded one bracket. Con- seas ______ 0.0575 <0.01-Q.1 -------- flrmation is indicated by these 

tests. No explanation is avaUable. 

So ____ 327a. 6 Synthetic_ •• 0.005 -------------- -------- o.oos 

3353.7 -------------- o. 001 .................................. -------- 3aS9. 7 0.007 ... -------------- -------------- -------- SL. •• 2506.9 Synthetic. __ 10.+ 10+-- -------- 11. If Si line 2881 is 3 to 4mm at 50 and 

243S. 2 C18b ______ 7.9 l.G-10.0 S.35 line 2506 A Is normal in width 

2506.9 F84------· 10.+ 1.Q-10.0 1a.1 but reads off the scale, use lfne 

2506.9 F9S _______ 10.+ l.Q-10. 0 1S.O 243S A because Si is under 10 

243S. 2 S29 ________ 7.9 l.Q-10.0 7.1 percent in these cases. 

243S.2 seas__ ____ 6.88 1.Q-10.0 4.45 

Sn ___ a17S. 0 Synthetic ___ 0.1 -------------- -------- o.oos Sn line a262 A satisfactory. 

3262.3 -------------- 0. ooas -------------- -------- Sr •••• 3646.5 Synthetic ___ 0.008 0.01-Q.1 ................... o.os A survey for more satisfactory 

3a8o. 7 C18b ______ 1. 0.1-1.0 0.45 strontium lines is in progress, 

a464. s -------------- 1. -------------- ................... a464. s F84.- ----- o.os O.Ol-Q.1 -------- 3464. s F9S. _ ----- 0.26 0.1-1. 0 ................. 3464.5 S29 ________ 0.07 0.1-1.0 -------- 3464. s seas ______ 0.67 0.1-1. 0 -------- TL •• 3236.6 Synthetic. __ 0.085 0.1-1.0 -------- 0.5 A survey for more satisfactory 

3242.0 -------------- 0.05 -------------- -------- titanium lines is in progress. 

3242.0 CI8b ______ ---------- 0.01-Q.1 0.06 3242 A is satisfactory in 0.01-1.0 

3242.0 F84------- ---------- 0.1-1.0 0.36 percent range. 

3242.0 F9S _______ ........................ 0.1-1.0 0.36 

3242.0 S29 ________ 0.08 0.01-Q.l 0.06 

3242.0 seas__ ____ 0.071 0. 01-{).1 0.06 
78 CONTRIBUTIONS TO GEOCHEMISTRY 

TABLE 2.-Spectru~ lines used and comparison. of spectographic and. chemical 

analyses of ashes-Continued 

Ele- Line (ang- ment strom) 

Th~-- 2837.3 

2870.4 

v ____ 3267.7 

3276.1 

3276.1 

a276.1 

a276.1 

a276.1 

Y •••. a327. 9 

a242.3 

3216.7 

a327. 9 

a327. 9 

a327. 9 

3327.9 

Yb ••• a289. 4 

Zn .• _ 3345.0 

aa45.0 

Zr ____ a391. 9 

a27a.o 

a27a.o 

a27a.o 

a273.0 

Sample 

Synthetic. __ 

--------------

Synthetic. __ C18b ______ 

F84 _______ 

F95 _______ 

S29 ________ 

seas.. ____ 

Synthetic ••. 

--------------

................................. Cl8b ______ 

F84 _______ 

S29 ________ 

seas__ ____ 

Synthetic. __ Cl8b ______ 

F84 _______ 

S29 ______ --

seas__ ____ 

Synthetic ___ 

-------------- Synthetic ___ 

F84 •• ~---- seas ______ 

C18b. _____ 

S29 ________ 

Spectrographic 

Microphotometric 

scanning 

(pe-rcent) 

0. 7 

0.4 

0.009 

0.0036 

0.009 

0.0087 

0.044 

o.oa 

0.0062 

0.0075 

0.019 

0.017 

0.01 

·---------

----------

<0.001 

---------- 0.002 

----------

---------- 0.006 

0.008 

o.oa 

0.008 

0.036 

0.17 

0.004 

Visual 

(percent) 

0.1-1. 0 

0.1-1. 0 

0.001-{).01 

0. 01-{).1 

0.01-{).1 

0.01-o.1 

0. 001-{).01 

0. 01-{).1 

0. 001-{).01 

0.001-o. 01 

.. ............................. 

0. 001-o. 01 

0. 01-{).1 

0.001-o. 01 

0.001-{).01 

0:001-{).01 

0.001-{).01 

0.001-o. 01 

--------------

-------------- 0. 001-{).01 

0.001-{).01 

0. 01-{).1 

0.1-1.0 

0.1-1.0 

0. 01-{).1 

0.001-{).01 

Chern- True 

ical value 

(per- ' (per- cent) cent) 

0.5 

0.005 

0.005 

--------

0.005 

-~- ----- -------- 0.05 

0.05 

Remarks 

These lines are satisfactory when 

uranium is less than 1 percent. 

3267 and 3276 A are satisfactory 

for low vanadium. 

3327 and 3242 A are satisfactory. 

Search for better lines in progress. 

Search for better lines)ndicated. 

Line aa92 A satisfactory when 

background is low. Linea27aA 

satisfactory when copper is low. 

Elements looked for but not found: Au, Bi, Cd, Ce, Cs, Dy, Er, Eu, F, Gd, Hf, Hg, Ho, In, Ir, La, Lf, 

Lu, Nb, Nd, Os, Pd, Pr, Pt, Rb, Re, Rh, Ru, Sb, Sm, Ta, Tb, Te, Tl, U, and W. 
SPECTROGRAPHIC MICROPHOTOMETRIC SCANNING 79 

TABLE 3.-Standard sensitivities for the elements determined by the microphotometric 

scanning method 

Percent Percent Percent 

Ag_- ---- 0.00001 HL _____ 0.03 Re ______ 0.04 Al _______ .0001 Hg ______ .08 Rh ______ .004 As _______ .01 Ho ______ .001 Ru_ ----- .008 Au ______ .001 In ____ ~-- .0004 Sb _______ .01 B _______ .005 Ir _______ .. 03, Sc __ · ___ -- .001 

Ba ______ .001 *K ______ .005 (0.3) SL ______ .005 Be ______ .00005 La ______ .003 Sm ______ .008 

BL ______ .005 *Li_ _____ .00003 (0.04) Sn _______ .004 

Ca ______ .01 Lu ______ .005 Sr _______ .001 

Cd __ ---- .005 Mg ______ .00003 Ta ______ .1 Ce ______ .03 Mo ______ .0005 Tb_ ----- .01 

Co __ ---- .008 Mn ______ .0007 Te ______ .08 

Or ___ ~--- .0006 Nb ______ .001 Th_ ----- .08 

*Cs--~--- .01 (0.8) *Na __ ~-- .0003 (0.01) Ti_ ______ .0005 Cu ______ .00005 Nd ______ .006 TL ______ .04 

Dy_~---- .006 NL ______ .005 Tm ______ .001 

Eu_ ----- .003 Os _______ .1 u _______ .08 

Er _______ .003 p _______ .07 v _______ .001 

**F----- .08 Pb ______ .001 w _______ .07 Fe _______ .0008 Pd __ ---- .003 y _______ .003 

Ga ______ .004 Pr _______ .01 Yb ______ .0003 Gd ______ .006 Pt _______ .003 Zn ______ .008 Ge __ _. ___ .001 *Rb _____ .007 (7) Zr _______ .0008 

• A second exposure Is required for the high sensitivity listed. 

•• A third exposure is required for fluorine estimation. 

TABLE 4.-S'/!-mmary of lines used, percentage range, and rating of line in 

spectrographic analysis of ashes. 

I Element Line EA) Range (percent) Rating 

Ag ______________________________ _ 

Al ___ _. ___________________________ _ 

As ____________________________ : __ _ 

B---~----------------------------

Ba ____ ----:---------------------·--

Be-------~----------------------­

Ca-------~-----------------------

Co __ ~---------------------------- Cr ________ ~----------------~------

Cu_~-----~-------------------: __ _ 

Fe-------------------------~------

3280. 7 

2575. 1 

2652. 5 

3059. 9 

2680. 5-

2497. 8 

2335. 3 

2348. 6 

2997. 3 

3000. 9 

3009. 2 

3453. '5 

2835. 6 

3247. 6 

3274. 0 

2936. 9 

2953. 9 

2599. 4· 

3008. 1 

0. 0001-0. 001 

10. + 

10. + 

1. 0-10. + 

0. 1-1. 0 

0. 01-1. 0 

0. 1-1. 0 

0. 0001-0. 001 

1. 0-10. 

1. 0-10. 

1. 0-10. 

0. 01-0. 1 

0. 01~0. 1 

0. 001-0. 1 

0. 001-0. 01 

1. 0-10. 

1. 0-10. 

10. + 

10. + 

Good. 

Good. 

Good. 

Fair. 

Fair. 

Good. 

Good. 

Fair. 

Good. 

Good. 

Fair. 

Good. 

Good.· 

Fair.· 

Fair. 

Fair.· 

Fair. . 1 

Fair. 

Fair. 

,.;. 
80 CONTRIBUTIONS TO GEOCHEMISTRY 

' TABLE 4.-Summary of lines used, percentage range, and rating of line in 

spectrographic analysis of ashes-Continued 

Element Line (A) Range (percent) Rating 

Ga _______________________________ 2943. 7 0. 001-0. 01. Poor.t Ge ________________________________ 3039. 1 0. 001-0. 01 Fair. ]{ ________________________________ 3446. 6 0. 1-10. Fair. 

Mg---------.---------------------- 2778. 3 1. 0-10. Fair. 

2779. 9 0. 1-1. 0 Fair. 

2781. 4. 0. 1-1. 0 Poor. 

2798. 0 0. 1-1. 0 Fair. 

Mn----------------------------~-- 2593. 7 0. 01-1. Good. 

2576. 1 0. 01-0. 1 Good. 

. 2605. 7 0. 01-0. 1 Fair . 

2801. 1 0. 1-1. 0 Fair. Mo _______________________________ 3170. 4 0. 001-0. 01 Good. 

3132. 6 o. 001-0. 01 Good. 

3122. 0 0. 01-0. 1 Good. 

3122. 0 0. 1-1. 0 Good. 

~a------------------------------- 3302. 3 1. 0-10. + Fair. 

3302. 9 1. 0-10. Fair. 

~i ____ ------------ _-:.~------------- 3393. 0 0. 01-0. 1 Poor.· 

3423. 7 0. 01-0. 1 Fair. 

3414. B 0. 01-0. 1 Fair. 

p ________________________________ 2535. 6 0. 1-1. 0 Fair. 

Pb------------------------------~ · 2833. 1 0. 01-1. 0 Poor. 1 

Sc ________________________________ 3273. 6 0. 001-0. 01 Good. 

3353. 7 9· 901-0. 01 Poor. 

3359. 7 0. 001-0. 01 Good. 

Si~------------------------------- 2506. 9 10. + Good. 

2435. 2 1. 0-10. Good. 

Sn---~--~----------------------: __ 3175. 0 0. 001-0. 01 Poor. 

3262.3 0. 001-0. 01 Fair. Sr ________________________________ 3464. 5 0. 001-0. 01 Poor. 

3380. 7 0. 01-0. 1 Fair. 

TL--------------------------~---- 3236. 6. 0. 01-1. Poor. 

3242. 0 0. 01-1. Good. 

Th------------------------------- 2837. 3 0. 1-1. Poor. 

2870. 4 0.1-1.- Poor. 

V--------------~----------------- 3267. 7 0. 001-0. 01 Fair. 

3276. 1 0.001-0.01 Good. 

y ________________________________ 3327. 9 0. 001-0. 01 Good. 

3242. 3 o. 001-0. 01 Good. 

3216. 7 0. 001-0. 01 Fair. Yb _______________________________ 3289. 4 o. 001-0. 01 Fair. Zn_: _____________________________ 3345. o· 0. 001-0. 01 Poor. 

Zr--~----------------------------- 3391. 9 0. 01-0. 1 Good. 

3273. 0 0. 01-0. 1 Good. 

1 Dow:ngrading the spectrographic results by a factor of 10 will bring chemical and spectrographic analyses 

In agree!llent. No explanation is available at present. 

U. S. GOVERNMENT PRINTING OFFICE: 1958