Rapid Screening Of Carbaryl In Vegetables And Fruits By Surface Enhanced Raman Technique

Carbaryl,also known as carbaryl,is chemically known as 1-nap Hthalenol methylcarbamate.It is a toxic pesticide in carbaryl,which inhibits acetylcholinesterase.Hydrolysis of acetylcholine to accumulate poisoning,can enter the human body through absorption and food,and can also cause poisoning through skin contact.Carbaryl has a good insecticidal effect and has good insecticidal effects against planthoppers,aphids and moths.However,due to its repeated use,a large number of pesticides remain in the water and soil,and the carbinol has a good insecticidal effect.Soil adsorption,limited degradation,and teratogenic mutations in products after degradation can seriously damage the environment and affect human health.At this stage,it is widely used in vegetables and fruits and has received much attention.In this paper,the surface-enhanced Raman spectroscopy(SERS)technique was used to establish a rapid screening method for the remnants of different vegetable and fruit substrates.The pre-treatment operation is simple and fast,the instrument and equipment are convenient to apply,the detection time is short,and the accuracy of the result is high.It provides a basis for further in-depth study of the testing of carbaryl and provides a convenient technique for on-site screening.The research contents and results of this paper are as follows:(1)The gold sol substrate with a particle size of 50 nm was successfully prepared.The silver sol substrate with a particle size of 48 nm was purchased and characterized by transmission electron microscopy and UV-visible spectroscopy.Rhodamine 6G was then selected as a probe molecule to verify the stability of the substrate.The experimental results show that in order to ensure the consistency of the subsequent experiments,the gold sol substrate should be re-prepared every 21 d,and the nano-silver substrate should be used within 28 days after purchase.(2)According to the peak assignments in the reference,it is determined that the sensory can be detected by SERS technology,and is 1564 cm-1,1435 cm-1,1377 cm-1,1160 cm-1,1062 cm-1,1029cm-1,999 cm-1,and 730 cm-1 have their response signals;the signal response of 1377 cm-1 is the strongest,which is designated as the characteristic peak of carbaryl,so that the experimental conditions are single factor and positive.The experimental results were optimized.The result was a concentrated gold sol as a reinforcing substrate.The 0.5 mol/L Na Cl solution(p H=6)was used asan agglomerating agent.The detection system was 100 ?L sol substrate-200 ?L target to be tested-100 ?L agglomerating agent,linear range The correlation was0.129 g/kg,the correlation was 0.9928,the linear regression equation was y = 449.34x+ 264.38,the detection limit was 0.1 ?g/kg,and the precision was 2.33% ~ 4.23%.(3)Selecting cucumber and spinach as samples to optimize the screening conditions of vegetable substrate.The result is that the concentrated gold sol is the reinforcing substrate,the agglomeration agent is 0.5mol/L Na Cl solution(p H=9),and the detection system is 100?L.Sol substrate-250?L sample solution to be tested-100 ?L of agglomerating agent.In this experiment,leafy vegetables(spinach)and melons and vegetables(squash)were taken as examples to investigate the matrix interference of different vegetables.The vegetable substrate was screened under optimized conditions.The results showed that the detection limit of cucumber was 10?g/kg,and the linear relationship was good in the concentration range of 10?g/kg ~50?g/kg,y = 3.8827 x + 33.548,R2 = 0.9908,Three concentration points of 14?g/kg,27?g/kg and 35?g/kg were selected,the recovery rate was 93.66~102.65%,the precision RSD<5%;the detection limit of spinach was 100?g/kg,at 100?g/kg~500?g/ The k-concentration range has a good linear relationship,y = 0.3152 x +41.758,R2=0.9916,and three concentration points of 130?g/kg,280?g/kg,and410?g/kg are selected,the recovery rate is 98.59~102.31%,and the precision RSD<5%.(4)Select apple and orange as samples to optimize the screening conditions of the fruit matrix.The result is that the concentrated gold sol is the reinforcing substrate,the agglomeration agent is 0.5mol/L Na Cl solution(p H=9),and the detection system is 100?L sol.Substrate-25?L of sample solution to be tested-100?L of agglomerating agent.In this experiment,deciduous tree fruit(apple)and small tree fruit(orange)were taken as examples to investigate the matrix interference of different fruits.The fruit substrate was screened under optimized conditions.The results showed that the detection limit of apple was 5?g/kg,and the linear relationship was good in the concentration range of 5?g/kg ~45?g/kg,y = 2.7267 x + 96.191,R2=0.9913,choose 16?g/kg,28?g/kg,37?g/kg three concentration points,the recovery rate is 98.41~100.95%,the precision RSD<5%;the detection limit of orange is 50?g/kg,50?g/kg ~400?g/kg The linear range of concentration range was good,y =0.0876 x + 31.568,R2=0.9906,three concentration points of 142?g/kg,235?g/kg and330?g/kg were selected,the recovery rate was 96.72~100.31%,and the precision RSD<5%.