Supporting information
Application of optimized dispersive nanomaterial-ultrasound
assisted microextraction method for preconcentration of
carbofuran, propoxur, and their determination by HPLC-UV
Saeid Khodadoust*a, Mohammad Sharif Talebianpoora, Mehrorang Ghaedib
a
Medicinal plants Research Center, Yasuj University of Medical Science, Yasuj, Iran
b
Department of chemistry, Yasouj University, Yasouj, Iran
* Corresponding author, Email: saeid.kh64@gmail.com, Tel/Fax: +98 741 2223048
Abstract
An
extraction
method
based
on
dispersive
nanomaterial-ultrasound
assisted
microextraction (DNUM) was used for the preconcentration of carbofuran and propoxur
insecticides in water samples prior to high performance liquid chromatography-ultra violet
detection (HPLC-UV). ZnS:Ni nanoparticles were synthesized based on the reaction of the
mixture of zinc acetate and nickel acetate with thioacetamide in aqueous media and then loaded
on activated carbon (AC) (ZnS:Ni-AC). Different methods were used for recognizing the
properties of ZnS:Ni-AC and then this nanomaterial was used for extraction of carbamate
insecticide as new adsorbent. Influence variables on the extraction method (such as amount of
adsorbent (mg: NiZnS-AC), pH and ionic strength of sample solution, vortex and ultrasonic time
(min), ultrasonic temperature and desorption volume (mL)) were investigated screening 27–4
Plackett–Burman (PB) design. Then the significant variables were optimized by using a central
composite design (CCD) combined with desirability function (DF). At optimum conditions
method had linear response over 0.0060-10 µg mL−1 with detection limit 0.0015 µg mL−1 with
relative standard deviations (RSDs) less than 5.0% (n = 3).
Table S1. Properties of NiZnS-AC obtained from BET data.
Single point surface area at p/p°
1009.485 m² g-1
BET Surface Area
1012.752 m² g-1
Langmuir Surface Area
1380.726 m² g-1
t-Plot Micropore Area
476.042 m² g-1
t-Plot External Surface Area
536.710 m² g-1
BJH Adsorption cumulative surface area of pores
between 17.000 Å and 3000.000 Å width
133.041 m² g-1
BJH Desorption cumulative surface area of pores
between 17.000 Å and 3000.000 Å width
157.046 m² g-1
Single point adsorption total pore volume of pores
less than 1190.518 Å width at p/p°
0.552 cm³ g-1
t-Plot micropore volume
0.214 cm³ g-1
BJH Adsorption cumulative volume of pores
between 17.000 Å and 3000.000 Å width
0.155 cm³ g-1
BJH Desorption cumulative volume of pores
between 17.000 Å and 3000.000 Å width
0.162 cm³ g-1
Adsorption average pore width (4V/A by BET)
21.798 Å
BJH Adsorption average pore width (4V/A)
46.510 Å
BJH Desorption average pore width (4V/A)
41.292 Å
Surface Area
Properties of NiZnSAC
Pore Volume
Pore Size
Table S2: Variables, codes, low and high levels in 27–4 Plackett–Burman design matrix.
Factors
Levels
(X1) Adsorbent (mg: NiZnS-AC)
(X2) pH of sample solution
(X3) Ionic strength (NaCl % (w/v)
(X4) Vortex time (min)
(X5) Ultrasonic time (min)
(X6) Ultrasonic temperature ( ˚C)
(X7) Desorption volume (mL)
Run
1
2
3
4
5
6
7
8
9 (C)
10 (C)
X1
-1
+1
-1
+1
-1
+1
-1
+1
0
0
C: center point
X2
-1
-1
+1
+1
-1
-1
+1
+1
0
0
X3
-1
-1
-1
-1
+1
+1
+1
+1
0
0
X4
+1
-1
-1
+1
+1
-1
-1
+1
0
0
Low (-1)
Center point (0)
High (+1)
5.0
3.0
2.0
2.0
1.5
20.0
0.5
10.0
7.0
5.0
4.0
3.0
30.0
1.0
15.0
11.0
8.0
6.0
4.5
40.0
1.5
X5
+1
-1
+1
-1
-1
+1
-1
+1
0
0
X6
+1
+1
-1
-1
-1
-1
+1
+1
0
0
X7
-1
+1
+1
-1
+1
-1
-1
+1
0
0
ER %
57.73
70.97
53.36
70.29
54.43
70.02
40.64
77.13
64.79
65.54
Table S3. Design matrix for the 23 central composite designs.
Factors
(X1) Adsorbent NiZnS-AC (mg)
(X2) Vortex time (min)
(X3) Ultrasonic time (min)
Low (−1)
Levels
Central(0)
High(+1)
7.0
3.0
3.0
12.0
5.0
5.0
17.0
7.0
7.0
Star point
-α
+α
α=1.682
3.6
20.4
1.6
8.4
1.6
8.4
Runs
X1
X2
X3
ER %
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15(c)
16(c)
-1
-1
-1
-1
1
1
1
1
-1.682
1.682
0
0
0
0
0
0
-1
-1
1
1
-1
-1
1
1
0
0
-1682
1.682
0
0
0
0
-1
1
-1
1
-1
1
-1
1
0
0
0
0
-1.682
1.682
0
0
50.24
57.11
57.64
72.31
74.18
70.62
76.48
85.35
45.53
78.81
59.67
82.34
68.84
83.21
87.67
88.93
C: center point
Table S4. Comparison of DNUM-HPLC-UV with other extraction methods for determination of
carbofuran and propoxur.
Method
LOD (µg mL−1)
SPME–HPLC–
UV
MSA-DLLME–
HPLC–DAD
G-Fe3O4-HPLCDAD
DNUM-HPLCUV
RSD (%)
0.001
Linear range
(µg mL−1)
0.005–10
Reference
1.7–5.3
Extraction time
(min)
25
0.0004
0.002–1.0
4.0-5.0
5
[47]
0.00002
0.0001–0.05
3.0-5.0
15
[48]
0.0015-0.0020
0.0060-10
0.0070-10
3.8-4.5
12
Present work
[46]
Figure S1. A schematic diagram of the extraction process.
Figure S2. a) Plot of predicted value vs observed value for extraction recovery of carbofuran and
propoxur. b) Plot of residuals versus predicted response for extraction recovery of carbofuran
and propoxur.