Analytical Sciences

Abstract − Analytical Sciences, 18(2), 171 (2002).

Analysis of Residual Solvents inAmpicillin Powder by Headspace Spectrophotometric Method
Department of Chemistry, Faculty ofScience, Urmia University, Urmia, Iran
In this study a headspace spectrophotometricmethod is proposed for analysis of dichloromethane and isobutyl methylketon (IBMK) residues in the ampicillin powder. Ampicillin is dissolved in1 M NaOH in the vessel of an arsenic analyzer unit of an atomic absorptionspectrophotometer. After 3-min stirring, the headspace has flowed by airinto the flow-through cell and its absorbance is read at 196 nm, as emittedby a selenium hollow cathode lamp. The absorbance of the headspace is readin two cases (in the presence and absence of MnO4-ion). In the former case, the absorbance is only related todichloromethane; in the latter, it is related to both solvents. By thismethod both solvents are determined in the ampicillin samples. Theobtained results are compared with gas chromatography (GC) data. Theseresults have good agreement. The proposed method is very rapid, selectiveand repeatable. Other solvents present, such as isopropyl alcohol,ethylacetate and triethylamine, are not interfering.