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Electronic Supplementary Material
Electrochemical simultaneous assay of chloramphenicol and PCB72 using magnetic and
aptamer-modified quantum dot-encoded dendritic nanotracers for signal amplification
Meng Chen,a Ning Gan*a, Huairong Zhanga, Zhongdan Yana, Tianhua Lia, Yinji Chenb, Qing
Xu**a and Qianli Jiangc
a
State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty
of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, China.
b
Faculty of Food Science and Engineering, Nanjing University of Finance and Economics,
Nanjing 210000, China.
c
Department of Hematology, Nanfang Hospital, Southern Medical University, Guangzhou
510515, China.
* Corresponding author, Email: [email protected], Tel: +86-574-87609987; Fax:
+86-574-87609987
** Corresponding author, Email: [email protected]
Experimental Section
Preparation of Fe3O4 nanoparticles
Fe3O4 nanoparticles were synthesized through a solvothermal reaction. Typically, FeCl3·6H2O
(8.1 g) and sodium acetate anhydrous (NaAc, 21.6 g) were dissolved in 300 mL of ethylene
glycol under magnetic stirring for 30 min. Subsequently, the homogeneous yellow solution
was transferred to Teflon-lined stainless-steel autoclaves and sealed to heat at 200 °C. After
reaction for 8 h, the autoclaves were cooled to room temperature. The obtained black Fe3O4
nanoparticles were separated by a magnet and washed three times with deionized water and
ethanol respectively. Finally, they were dried under vacuum at 60 °C.
Preparation of the Fe3O4/Au nanoparticles
Magnetic gold nanoparticles (Fe3O4/Au) were synthesized with our previously reported
method [41]. In brief, 0.02 g Fe3O4 NPs was dispersed in 5 mL 3% PDDA aqueous solution
and then stirred for 30 min. After magnetic separation and removal of the unbounded PDDA,
the resulting solid was spreaded in 130 mL Au NPs solution and stirred for 8 h at room
temperature. The dark purple Fe3O4/Au NPs were obtained until the supernatant was colorless
through magnetic separation. After washed several times with deionized water and ethanol
respectively, the Fe3O4/Au NPs were dispersed into 100 mL ultrapure water. Prior to use, the
solution was stored at 4 °C.
Fig. S1 TEMs and their size distributions of CdS/EV (a) and PbS / EV (b).
Fig. S2 EIS of bare GCE (a) and Bismuth film modified GCE (b) at frequency range 0.1–1.0×105 Hz.
Fig. S3. The effect of the different volume ratio of CdS (a), PbS (b) QDs to EV.
Fig.S4. Effect of (a) Incubation time and (b) Incubation temperature and (c) PH on the stripping peak
current using 10 ng mL-1 CAP and PCB72.
Fig. S5. SWVs responses (a) and calibration plots of CAP (b) and PCB72 (c) at different
concentrations (from 0.001 ng mL-1 to 100 ng mL-1).
Table S1 Comparison of the detection limit and linear range of different determination assays
References
Method
Solid
[1]
phase
chromatography
Detection limit
Linear range
microextraction—Liquid
(SPME-LC)
determination
of
0.1 ng mL-1
0.1 -10 ng mL-1
0.82 ng mL-1
2.0 -200 ng mL-1
0.03 ng mL-1
0.1-300 ng mL-1
0.39 ng mL-1
0.3-100 ng mL-1.
0.5 ng mL-1
0.1 -100 ng mL-1
chloramphenicol
Amperometric immunosensor for chloramphenicol
[2]
dcetection
Electrochemical sensor for the determination of
[3]
chloramphenicol
Direct
electrochemical
immunosensor
for
[4]
polychlorinated biphenyls
aptamers against polychlorinated biphenyls as
[5]
potential biorecognition elements for PCB77
[email protected] in the multi-residue analysis of
0.02 ng g-1 (PCB28)
[6]
1-500 ng g-1
pesticides and PCBs by GC–MS/MS
0.33 pg mL-1 (CAP)
0.0001-100 ng mL-1
The proposed method
0.35 pg
mL-1 (PCB72)
Table S2. The spiked recovery of CAP and PCB72 for fish sample.
Found
Added
Detection
Samples
Recovery (%)
(ng mL-1)
( ng mL-1)
( ng mL-1)
number
CAP
PCB72
0.014±0.00
0.053±0.00
3
8
0.026±0.00
0.061±0.00
5
7
0.089±0.00
0.021±0.01
6
0
1
2
3
CAP
PCB72
CAP
PCB72
CAP
PCB72
0.050
0.050
0.062
0.099
96.0±3.7
92.0±4.6
0.100
0.100
0.128
0.155
102.0±6.2
94.0±7.6
1.000
1.000
1.053
0.998
96.4±4.3
97.7±4.8
2.500
2.500
2.492
2.553
99.7±7.4
101.1±5.2
5.000
5.000
5.106
4.890
102.1±5.4
97.8±3.9
0.025±0.00
4
ND
6
5
ND
ND
ND: not found
References
[1] Aresta A, Bianchi D, Calvano C D, Zambonin C G (2010) Solid phase
microextraction—Liquid chromatography (SPME-LC) determination of chloramphenicol
in urine and environmental water samples. J Pharm Biomed Anal 53 (3): 440-444.
[2] He G, Yang X, Hu Y, Hu Y, Zhang F (2014) A Sensitive and Selective Amperometric
immunosensor for chloramphenicol detection based on magnetic nanocomposites modify
screen-printed carbon electrode as a disposable platform. Int J Electrochem Sci 9:
6962-6974.
[3] Liu G, Chai C (2015) Towards the development of a sensitive electrochemical sensor for
the determination of chloramphenicol residues in milk. Anal Methods-UK 7(4):
1572-1577.
[4] Bender S, Sadik O A (1998) Direct electrochemical immunosensor for polychlorinated
biphenyls. Environ Sci Technol 32(6): 788-797.
[5] Xu S, Yuan H, Chen S, Xu A, Wang J, Wu L (2012) Selection of DNA aptamers against
polychlorinated biphenyls as potential biorecognition elements for environmental analysis.
Anal Biochem 423(2): 195-201.
[6] Peng X, Jiang L, Gong Y, Hu X Z, Peng L J, Feng Y Q (2015) Preparation of mesoporous
ZrO 2-coated magnetic microsphere and its application in the multi-residue analysis of
pesticides and PCBs in fish by GC–MS/MS. Talanta 132: 118-125.
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