| Summary: | Ampicillin and vancomycin are chemical substances used as antibiotics to treat and
prevent disease development. The conventional methods used in detecting these
residues suffered some drawbacks of being expensive, time consuming and lack the
capacity for point of care analysis.In this work technological detection based on
nickel nanoparticle (NiNP) was developed. NiNP was synthesizedusing hydrazine,
polyvinylpyrrollidone, aqueous sodium hydroxideand 3-aminopropyl-triethoxysilane
(APTES) as a crosslinker is presented here. The amine groups in APTES were used
as growth point for the NiNP synthesis through electrostatic attraction between the
amine group (NH4
+) and Ni(II) chloride- while sodium hydroxide acts as a reducing
agent. Nickel nanoparticle has properties ofconductivity and catalytic particles that is
intensively exploited for electrode modification.The synthesized particle
demonstrates average size distribution of nanoparticle of about 50 nm. The energy
dispersive X-ray was conducted to find the elemental composition of the
nanoparticle while X-ray diffraction measurement identify the phase and crystallinity
of nickel nanoparticle. The Field emission scanning electron microscopy reveal that
the formed nanoparticle are dominantly spherical in shape and evenly distributed.
The attachment of the carboxylic group(-COOH) to the surface of nanoparticle is
confirmed by FTIR. As evidenced by electrochemical measurements, these surface
nickel nanoparticle generates substantial surface area. For bare SPCE, the active
surface area was calculated to be 0.034 cm2 while the effective surface area of
modified SPCE with nickel nanoparticle was found to be 0.084 cm2. Effect of
parameters such as pH, buffer, scan rate, accumulation potential, accumulation time
and concentration on the sensitivity of fabricated sensor were optimized. Under the
optimized conditions, there were two linear calibration ranges from 0.01–0.5 μM
with regression equations of Ip(μA) = 350.749C + 1.0443, correlation coefficient of
0.9996 for ampicillin and Ip(μA) = 340.618C + 14.704 correlation coefficients of
0.9993 for vancomycin, respectively. Moreover, an excess of a quadratic mixture of amoxicillin, penicillin G, Vancomycin, changed less than 5.0 % of the ampicillin
signal. This suggests that the fabricated sensor has a satisfactory selectivity for
determination of ampicillin and vancomycin. The reproducibility and stability of
NiNP were investigated using cyclic and differential pulse voltammetry
measurements of 10 μM ampicillin and vancomycin. The relative standard deviation
(RSD%) for seven successive assays of ampicillin and vancomycin was 1.83 and
1.92. When the electrode was stored in the laboratory at room temperature to
determine its stability, the modified electrode retained 87% and 85% their initial
response for a period of 28 days. These results indicate that NiNP on SPE has good
stability and reproducibility, and can be used to detect antibiotics at low
concentration either in waste or food samples. The 10 μM of ampicillin and
vancomycin under the optimized conditions were used to determine the interference
of other species. The results obtained indicate that the interference species have less
than 5% peak currents in each analysis. The limit of detection and limit of
quantitation for ampicillin were calculated as 0.00031 μM and 0.00300 μM, and that
of vancomycin is 0.00041 μM and 0.00135 μM respectively. The developed
electrochemical sensor based on nickel nanoparticle modification system and Aptes
as a binder is applied in the detection of the antibiotics.
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