Page 41 - LC-SFC_Pharma_Brochure

As sx‘(λy) and sy’(λx) are non-zero constants in equations (1) and Fig. 3 shows the absorbance chromatogram at 235 nm and de-
st
(2), it can be seen that the derivative spectrum chromatogram at rived spectrum chromatogram at 1 derivative zero wavelength
wavelength λx shows the elution profile for component y only, under several types of analytical conditions.
and the derivative spectrum chromatogram at wavelength λy In (a), the impurity is detected using i-PDeA, even though MN and
shows the elution profile for component x only. its impurity overlap chromatographically.
That is, the derivative spectrum chromatogram at wavelength λx In (b), MN and the impurity begin to separate chromatographical-
can separate component y only, and the derivative spectrum ly. By comparing the spectra at the apex of each peak, MN and
chromatogram at wavelength λy can separate component x only. the impurity can be confirmed to be different compounds.
In (c), MN and the impurity are completely separated chromato-
graphically. The derived spectrum chromatogram shows no sig-
1-2. Impurity Detection
nificant signal at the retention time of the MN peak, which shows
i-PDeA can detect whether impurity components exist in addition the signal of the MN peak does not include a contribution from
to the major component. This method can be applied when one the impurity.
major component is mixed with other impurity components. The As described in this example, whether impurity peaks are chro-
3D chromatogram S (t, λ) can be expressed as follows if the major matographically resolved or co-eluted with the main component,
component elution profile is denoted as px (t), the impurity com- i-PDeA easily detects their existence.
ponent elution profiles as py (t), pz (t)…, the major component
mAU
spectrum as sx (λ), and the impurity spectra as sy (λ), sz (λ)… 110 Ch1-235 nm, 4 nm Absorbance
S , (t ) λ = p x (t )s x (λ ) + p y (t )s y (λ ) + p z (t )s z (λ )... 100 Ch2-Derivative 241.81 nm chromatogram of MN
90
Then, the derivative spectrum chromatogram at wavelength λx at
80
which the major component derivative spectrum chromatogram
70
sx'(λ) value becomes zero is given by 60
∂S (t ) = p (t )s ( ' λ ) + p (t )s ( ' λ ) + ... 50 Derivative spectrum
∂λ λ =λ y y x z z x 40 chromatogram
x
Therefore, the derivative spectrum chromatogram at wavelength λx 30
20
eliminates the major component elution profile and expresses the 10
elution profiles of the impurities besides the major component. 0
0.21 0.22 0.23 0.24 0.25 0.26 0.27 min
(a) Mobile phase : Acetnirile95% / Water5%
mAU
2. Examples of Analysis Using 90 Ch1-235 nm, 4 nm Absorbance
the i-PDeA Functions 80 Ch2-Derivative 241.81 nm chromatogram of MN
70
2-1. Impurity Detection in 60 Impurity
Standard Samples 50
Derivative spectrum MN
40
This section demonstrates that an impurity in a methylnaphthalene chromatogram
(MN) standard was detected using the derivative spectrum chromato- 30 Spectra of MN and impurity
gram method. 20
10
Analytical Conditions
0
Pump : Shimadzu LC-30AD×2 0.300 0.325 0.350 min
Detector : Shimadzu SPD-M30A (b) Mobile phase : Acetonitrile85% / Water15%
Column oven : Shimadzu CTO-20AC mAU
Controller : Shimadzu CBM-20A 22.5 Ch1-235 nm, 4 nm
Autosampler : Shimadzu SIL-30ACMP 20.0 Ch2-Derivative 242.14 nm Absorbance
Column : Shimadzu Shim-pack XR-ODS chromatogram of MN
(30 mmL. × 3.0 mmI.D., 2.2 µm) 17.5
Flow rate : 1 mL/min 15.0
Column temp. : 40 °C
12.5
Sampling : 80 msec
Slit width : 1 nm 10.0 Derivative spectrum
Time constant : 240 msec 7.5 chromatogram
Wavelength range : 190 nm to 700 nm
Injection volume : 1 µL 5.0
2.5
0.0
1.6 1.7 1.8 1.9 2.0 2.1 min
(c) Mobile phase : Acetnitrile50% / Water50%
Fig. 3 Absorbance chromatogram and derivative spectrum chromatogram

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