Development and Validation of an HPLC Method for the Analysis of Chlorpropham and 3-Chloroaniline in Potato Extracts

Chlorpropham (CIPC) is the main sprout inhibitor used by potato industry. There is concern about the residues of CIPC and its degradation product 3-chloroaniline, 3-CA; hence, analytical methods are required to analyse their residues in potato samples. An HPLC-UV method was developed and validated for the separation and quantification of these compounds using propham (IPC) as an internal standard. The chromatographic conditions required to achieve good separation were 60% mobile phase of methanol, 15-minute run time at a flow rate of 1.5？mL/min, and a detection wavelength of 210？nm using Phenomenex (ODS-2 250？mm 4.60？mm 5？μm Sphereclone) column at an ambient temperature. The method was validated for precision, linearity, the limit of detection (LOD) and the limit of quantification (LOQ), producing high precision through RSD ≤ 0.03%, and acceptable criteria of the coefficient of determination () of the calibration curves (0.990). LOD values of CIPC and 3-CA were approximately 0.01？μg/mL whereas the LOQ values were approximately 0.04？μg/mL using repeated injection approach. The proposed HPLC method was compared with the standard GC method of the CIPC residues extracted showing good agreement . Despite using the same extract, the recovery results for the proposed HPLC method were 13% higher than GC analysis. 1. Introduction Chlorpropham (isopropyl 3-chlorophenyl carbamate) or CIPC is the main sprout inhibitor currently used by potato industry. Propham (IPC) is a herbicide from the same group as chlorpropham; it was applied commercially to prevent sprouting or in combination with chlorpropham, but currently its application is being banned in most countries. CIPC is a compound of the well-known group of N-phenyl carbamates which may undergo rapid degradation under unsuitable solvent and excessive heating conditions releasing 3-CA [1–5]. For public health and environmental consideration, there is concern about their residues [6, 7]; hence, analytical methods are required to analyse the residues of these phenylcarbamates in potato and environmental samples particularly CIPC and its degradation product 3-chloroaniline 3-CA. HPLC is used to determine carbamate pesticides residues mainly to overcome the thermal liability problems of these pesticides when using gas chromatography (GC). However, a lack of a specific, sensitive detector hinders a suitable level of separation for a number of pesticides. Adequate sensitivity and excellent specificity can be provided by ultraviolet (UV) or electrochemical HPLC detection [8]. Using HPLC-UV seems to be more appropriate