Feb. 1,1925 
The Quantitative Determination of Xanthophyll 
257 
of the colorimetric readings for xantho¬ 
phyll are based. The chart is used in 
a, manner similar to the chart for 
carotin in the paper 6 on carotin and 
consequently needs no explanation. 
Table II .—Lovibond slide readings of 
an ether solution of xanthophyll 
Lovibond 
slide yellow 
Ex¬ 
peri¬ 
ment 
No. 
Concentration of xanthophyll 
in milligrams per Mter 
a 
a 
o 
<N 
a 
a 
<D 
CO 
CO 
a 
a 
DJ 
»o 
tN 
a 
a 
0 
a 
a 
oq 
CO 
t-H 
a 
a 
06 
a 
a 
cs 
5. 
10 . 
20 __ 
1 
2 
3 
1 
2 
3 
1 
2 
3 
1 
0 . 60 0.80 
.50 .80 
.60 .75 
1 . 00 1.30 
1.10 1.30 
. 90 1. 20 
1. 60 1. 90 
1 . 70 2.10 
1 . 70 2 .10 
1 . 1 
".T 
1.7 
I.T 
2.8 
2.9" 
I.T 
2.00 
3. 3~ 
1.5 
1.6 
1.5 
2.7 
2.4 
2.3 
4.1 
4.3 
4.1 
2.9 
2.9 
2.9 
5.2 
5.2 
4.8 
8.0 
8.5 
7.7 
6.1 
5.6 
5.8 
10.2 
9.7 
9.5 
17.4 
15.9 
15.6 
Average_ 
5 
.56 
.78 
1.0 
1. 30 
1. 53 
2.90 
5.83 
10 
1.00 1. 26 
1. 65 
2.00 
2. 46 
5.06 
9. 80 
20 
1. 66|2.03 
2.85 
3.30 
4.16 
8.06 
16.30 
COMPARISON OF SPECTROPHOTO- 
METRIC AND COLORIMETRIC 
METHODS FOR THE QUANTITA¬ 
TIVE DETERMINATION OF XAN¬ 
THOPHYLL 
In the former paper on carotin de¬ 
termination it was shown that the 
spectrophotometer is superior to the 
colorimeter. 
The two methods were compared 
also in the case of xanthophyll. A 
solution of xanthophyll in alcohol 
was used for the test. On September 
6 and 7, both clear days, readings 
(Table III) were taken on the color¬ 
imeter each hour of the working day 
(fig. 4). Similar readings (Table IV) 
were taken on September 11, using 
the spectrophotometer. The 2-centi¬ 
meter cell of the spectrophotometer 
was refilled for each reading and the 
solution was diluted 20 times, using 
ether. The results on the colorimeter, 
using the solution undiluted, showed 
a variation of 61 parts in 358, or 17 
Fig. 3— Lovibond slide readings plotted to show the results obtained from different concentrations 
of xanthophyll in ether 
The reading in millimeters on the 
Duboscq colorimeter are plotted on 
the Y-axis while milligrams of xantho¬ 
phyll per liter of ether are shown on 
the X-axis. 
per cent while the spectrophotometric 
results, even after the solution used 
was diluted 20 times, showed a varia¬ 
tion of only 10 parts in 354 or 2.8 per 
cent. 
® SCHERTZ, F. MTHE QUANTITATIVE DETERMINATION OF CAROTIN BY MEANS OF THE SPECTROPHOTOM 
eter and the colorimeter. Jour. Agr. Research 26: 383-400, illus. 1924. 
