# A Correction Method of Mixed Pesticide Content Prediction in Apple by Using Raman Spectra
## 1 Introduction  
Pesticide plays an essential role in crop farming. Application of pesticide in agriculture has created a great deal of grain output and fed many people in the world. But this also caused some problems. Pesticides have chronic and acute impact to human health [1; 2; 3]. Pesticide poisoning to human health due to either processing during agricultural production or living poisoning that is because of consumption of food with high residuals, ingestion, residue and so on [4]. While in the detection of mixed pesticide residue, the interaction between different pesticide components always affects the intensity of characteristic peaks, which makes the detection results inaccurate. It's necessary to find a way to eliminate the interference. Deltamethrin (C\({}_{22}\)H\({}_{19}\)Br\({}_{2}\)NO\({}_{3}\)) is a kind of efficient synthetic pyrethroid insecticides which is created in 1974 with advantages like wide insecticidal spectrum, significant effect, low residue and so on. And deltamethrin has been widely applied in crops. While deltamethrin is also one of limited used pesticides. Some studies demonstrated that long-term intake of agricultural products with deltamethrin residue increased the risk of neurodegenerative disorders like Parkinson, Alzheimer disease, developmental deficits and learning disabilities [5; 6; 7; 8]. Thus it's quite necessary to detect deltamethrin for reducing damage to the public safety. In continuous contactto insecticides directly or indirectly may increases potential human health problems. It's necessary to reduce deltamethrin residue on fruits and vegetables to decrease contact. Relevant study on agricultural products had been done by some researchers. And on October 27 th 2017, deltamethrin was classified as category 3 carcinogens by World Health Organization (WHO) International Agency for Research on Cancer [9]. Acetamiprid(C\({}_{10}\)H\({}_{11}\)CIN\({}_{4}\)) is a synthetic chlorinated nicotinine pesticide against insects that have gained resistance to monophosphate, carbamate and synthetic pyrethroid. It has been widely used for agricultural pest control in many countries. In the experiment, long-term intake of high doses of acetaminophen will lead to breast cancer in adult mouse models and rib malformations in fetal mice. Acetamiprid also causes mutagenesis in human peripheral lymphocytes in vitro and synergistic mutagenesis effect with alpha-cypermethrin. In agricultural production, the alternate use or combination of deltamethrin and organophosphorus pesticides, such as non-pyrimid pesticides, is beneficial to slow down the development of pest resistance. Pesticide residue mixture of deltamethrin and acetamiprid residue always exists on crop. While compared with the characteristic peaks intensity of single deltamethrin and acetamiprid, the characteristic peaks intensity of the pesticides mixture is low in a certain range, which increases the difficulty in the detection. Raman spectroscopy is defined as a spectroscopic and imaging technique that is used to record or observe vibration, rotational or other lower frequency modes in a system [10]. It possesses strong advantages compared to other analytical techniques [11]. It is based on Raman scattering effect or inelastic vibration and known for its ability to detect chemicals accurately and precisely [12]. As Raman fingerprint of substance is distinctly unique to each other, it owns the ability to discern different element in the material [13]. The water molecule contains only a very small single chemical bond, which makes its Raman signal very weak [14]. During the Raman detection no samples will be touched by chemical substance. It had already been used in quality control of pesticide formulations [15]. [PERSON] developed a method to detect chloropyrifos on apples through Raman spectroscopy technology [16].