Research And Application Of SERS Technology Based On Nanocomposites In The Detection Of Several Aminoglycosides

Aminoglycosides（AGs）are widely used in the clinical field and animal husbandry industry because of their good effect and low price with some side effects such as ototoxicity and nephrotoxicity.Irregular and excessive drug use will make them accumulate in the body of human and animals,which will pose a great threat to the health of the ears and kidneys of human.The lack of absorbing groups in the structure of aminoglycoside drugs makes the direct spectral quantitative analysis of these drugs be a great challenge to realize.Surface enhanced Raman scattering（SERS）spectroscopy has the advantages of high sensitivity,good selectivity,simple sample pretreatment and field detection,which makes it a promising technology.In this paper,three kinds of nanocomposites were successfully prepared by hydrothermal synthesis method,and based on these materials,SERS detection methods of spectinomycin,isepamicin,gentamicin and tobramycin were established respectively.The main contents of the study were as follows:A SERS method with good selectivity and high sensitivity for the determination of spectinomycin was established based on silver nanoparticles（Ag NPs）coated by bovine serum albumin（BSA）and decorated withα-cyclodextrin（α-CD）.The SERS characteristic peak of spectinomycin at 485 cm^-1 was selected for quantitative analysis and the enhancement factor（EF）of the detection system was 1.95×10⁷.The synthesized substrateα-CD/BSA@Ag NPs was characterized by ultraviolet visible（UV-vis）spectroscopy and transmission electron microscope（TEM）.The interaction between the substrate and the drug was demonstrated by UV-vis and fourier transform infrared（FT-IR）spectroscopy.The effects ofα-CD/BSA@Ag NPs solution volume,Na Cl volume and mixing time on SERS signal intensity of spectinomycin were investigated by single factor and response surface experiments.The optimum conditions were 184μL substrate,130μL Na Cl addition and mixing time of 6minutes.Under the optimum conditions,the spectinomycin performed a good linear relationship with the Raman signal in the 3.33–1000.00 nmol·L^-1 concentration range(I_SERS=131.52 c+26585.53,c:nmol·L^-1,r=0.9960).Limit of detection（LOD）for this method was 2.01 nmol·L^-1（S/N=3）.The effects of interfering substances on the determination system were studied.The SERS method was successfully applied to the detection of spectinomycin in beef and lamb samples.The recovery of detection result in the samples was 96.04%–104.90%with relative standard deviation（RSD）2.27%–4.82%（n=5）.A SERS method for the determination of isepamicin using Ag NPs protected by BSA and modified byα-Fe₂O₃ as an efficient substrate was established.The EF of the detection system was 3.78×10⁶.The synthesized substrate and the combination of the substrate with drug were characterized by TEM,UV-vis,FT-IR and dynamic light scattering（DLS）.The experimental conditions were optimized by single factor and response surface experiments.The optimum conditions are determined as follows:substrate,Na Cl addition of 505μL,300μL and mixing time of 5 minutes.The influence of interfering substances on the determination results was studied.Under optimized conditions,a standard curve I_SERS=43.08 c+63598.69(c:nmol·L^-1)with a linear relationship（r=0.9976）was established between the SERS intensity and isepamicin concentration in the range of 20.00–2000.00 nmol·L^-1.The LOD of this method was 16.58 nmol·L^-1（S/N=3）.The recovery of isepamicin in the serum samples was 96.29%–104.12%with RSD 1.53%–3.43%（n=5）.The detecting methods for gentamicin and tobramycin utilizing SERS based onγ-Al₂O₃ modified BSA protected Ag NPs were established.The EFs of gentamicin and tobramycin detection systems were 2.44×10⁵ and 2.67×10⁶,respectively.The TEM,X-ray diffraction（XRD）,thermogravimetric analysis（TGA）and spectrophotometric techniques were used to characterize the substrate and the combination of the substance with drugs.The addition amounts for the substrate and Na Cl,as well as the mixing time were optimized by single factor and response surface experiments.The optimal conditions were 605μL,250μL,6 min for gentamicin and 545μL,450μL,（C）7 min for tobramycin.These methods had high selectivity proved by coexisting substances experiment.The concentrations of gentamicin and tobramycin showed good linear relationships with their Raman signals in the ranges of 66.67–2000.00and 6.67–300.00 nmol·L^-1and the standard curves of gentamicin and tobramycin were established as follows:I_SERS=20.50 c+51152.93(c:nmol·L^-1,r=0.9975)and I_SERS=46.26 c+39329.20(c:nmol·L^-1,r=0.9958).The LODs of these methods were 11.88 and 1.26 nmol·L^-1（S/N=3）,respectively.The recovery of gentamicin in commercial drug was 97.30%–101.80%（RSD=2.15%–2.68%,n=5）,and in beef and lamb samples was 96.75%–103.20%（RSD=1.89%–3.49%,n=5）.The recovery of tobramycin in commercial drug in the market was 98.90%–101.00%（RSD=1.27%–3.03%,n=5）,and in beef and lamb samples was 96.86%–100.70%（RSD=1.27%–4.85%,n=5）.