Please enable JavaScript.
Coggle requires JavaScript to display documents.
GAS CHROMATOGRAPHY-MASS SPECTROMETRY AND HIGHPERFORMANCE LIQUID…
GAS CHROMATOGRAPHY-MASS SPECTROMETRY AND HIGHPERFORMANCE LIQUID CHROMATOGRAPHY-DIODE ARRAY
DETECTION FOR DATING OF PAPER INK
-
-
-
RESULT & DISCUSSION
-
-
GC-MS method
Solvents used = Polar, apolar column gives better result
VF-WAXms(apolar column) = chromatography peaks less tailing, better resolution -> chosen for solvent analysis in this study
Internal standard = 3-methylphenol; 10 different concentration levels prepared ranging from 0.05-2.25mg/L; total mixture 5 mg/L
-
-
-
-
Multiple regression model:
T = a· X1 + b· X2 + c· X3 + ··· + d·Xi
T= ink exposure time
Xi= concentration of individual component
In black ink: BZA, PE, DH, MVBB, TP, pararosaniline (P) and MY contributed to the concentration
-
In blue ink: BZA, phenol (PH), PE, CV and TP contributed to the concentration
-
-
-
EXPERIMENTAL
GC-MS analysis
Use GC-MS with an Agilent 6850N/5975C equipped with an Agilent 7693A autosampler. DB-5MS 30m x 0.25mm i.d x 0.25 µm film thickness and and VF-WAXms 30m x 0.25mm i.d x
0.25 µm film thickness capillary columns were used
For data acquisition, MSD ChemStation software E.02.01 was used
For quantitative analysis, Agilent
Technologies® Deconvolutions Reporting A.0400 and NIST 2008 v.2.0. Mass Spectral Library-AMDIS Agilent Technologies®
(2010) were used
Was carried out under following conditions : injection volume 1µL,
splitless injection at 230ºC, GC column temperature starting at 45ºC, 1min isothermal, 8ºC/min to 230ºC, held for 5 min
Carrier gas was Helium (99,9997%) with a
constant flow rate of 1mL·min-1
-
-
Temperatures of the source and quadrupole were 230ºC and 150ºC,
respectively
MS analysis was carried out in SIM mode on the selected ions that
are characteristic of each compound
-
2.1.Chemicals, materials and samples
Methanol (HPLC gradient grade, 99.9%), n-hexane (gradient grade, 97%), acetonitrile
(HPLC gradient grade, 99.8%) and water are used for HPLC
A methanolic solution of 3-methylphenol was prepared as an internal standard at 1000 µg·mL-1
for the determination of solvents and dyes
Analytical standards used for calibration of all measured solvents can be refer to Table 1 in the journal
Black Montblanc and blue Montblanc ballpoint entries were drawn into a piece of white paper spaced evenly by the same researcher in order to maximize the uniformity of the ink traces
These ballpoint ink samples were deposited onto the paper 4 years prior to testing so it could be analyzed at intervals approximately 1 month and were stored in the dark in closed filing cabinets at room temperature with relative humidity during storage stayed within the interval 52-88%
A 1.25 mm diameter Harris micro-punch and a Harris cutting mat were used for sampling and small paper disc samples
of 1.25 mm diameter were cut using the micro-punch then placed into sealed amber
vials with 0.1 mL conical transparent glass inserts for analysis
2.2 EXTRACTION PROCEDURE
-
REAL SAMPLE
Step 2: Paper disc sample with inks deposit were placed into sealed amber vials with 0.1mL conical glass inserts.
Step 1: Age dating where 8 microdiscs were cut from each sample of black, blue ink on paper
Step 4: Then the sample was agitated in a closed vial with extraction solution for 30 s in an orbital shaker.
Step 5: Next, the pretreated sample was placed into ultrasonic bath for 2 minutes
Step 6: The following step, the samples were ready to be analyzed through GC-MS and HPLC-DAD to determine the concentration of dyes and pigment
Step 3: These discs were extracted with 15mL of MeOH solution (containing 0.1 mg/L of internal standard IS: 3-methylphenol)
-
-
