Development and Validation of an Automated Gas Chromatography Method for Determination of Dichloromethane in Ampicillin Sodium by Using Capillary Column Technology

Background: The main aim of the study was to develop an automated static headspace gas chromatography (SHS-GC) method for determination of dichloromethane (DCM) in ampicillin sodium by using a capillary column. Methods: SHS-GC also known as gas chromatography-headspace is the technique of choice due to its high sensitivity, excellent separation abilities, low limit of detection and simplicity of the instrumentation used for the technique. The headspace sampling method has more appropriate sensitivity than the direct injection method because it can clearly separate volatile analytes from the sample matrix and effectively concentrate them. Therefore, this method results in less complex sample preparation, decreased instrument contamination, and increased capillary column life. Results: The developed SHS-GC method showed symmetrical peak shape reasonable retention time for DCM. A linear relationship was obtained over the range of 2-240 μg mL-1 with a correlation coefficient (r2) of 0.993. The recovery, system precision and robustness of the method were within the acceptable values. The Limit of Detection (LOD) and Limit of Quantitation (LOQ) were 0.5 μg mL-1 and 2 μg mL-1 respectively. Conclusions: The results obtained in this study demonstrate that SHS-GC method is selective, precise, linear, accurate and robust for determination of dichloromethane in ampicillin sodium and its formulation (injection).