Determining Hydrogen Cyanamide in Fruit by Derivatization with 6-Aminoquinolyl-N-Hydroxysuccinimidyl Carbamate and HPLC with Fluorescence Detection

Hydrogen cyanamide is a plant-growth regulator used on fruit crops, and has a high toxicity. In this study, a simple and sensitive method for detecting hydrogen cyanamide in fruit was developed. In the proposed method, cyanamide was extracted with water from homogenized fruit samples (grape, kiwi, and peach). The extract was purified through twice liquid–liquid extraction. Then, the purified extract was derivatized with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate. Finally, the cyanamide derivative was analyzed using HPLC with fluorescence detection. This method was validated at 2, 0.2, and 0.01 mg kg⁻¹ cyanamide. The recovery rates were between 87.1 and 96.6 %, and the intraday and interday reproducibilities were within 1.8 and 2.2 %, respectively. The limits of detection and quantification were 2.4 and 8 μg kg⁻¹ cyanamide, respectively. This method was applied to explore the residue degradation of cyanamide in the field. The results show that the half-life of cyanamide residues on grapes was <2.0 days. Compared with the previous methods, this simple method is sensitive and can be applied for detecting cyanamide in a wide range of fruits.