Capillary Column Gas Chromatographic Determination of Trace Residues of the Herbicide Chlorsulfuron in Agricultural Runoff Water

Abstract A capillary column gas chromatographic method is described for determining parts-per-trillion (ppt) levels of chlorsulfuron in agricultural runoff water. The water sample is acidified with acetic acid and extracted with methylene chloride. The chlorsulfuron in the extract is derivatized to its monomethyl derivative. After Florisil column cleanup, the methylated chlorsulfuron is determined by electron-capture gas chromatography. Recovery of chlorsulfuron from fortified water samples is greater than 80%. Detection limit of the method is 25 ng chlorsulfuron/L water (25 ppt). There are 2 reaction sites on the chlorsulfuron molecule, both of which are susceptible to methylation leading to monomethyl chlorsulfuron and dimethyl chlorsulfuron. A procedure is described to methylate selectively the sulfonamide nitrogen of chlorsulfuron.</jats:p

Capillary Column Gas Chromatographic Determination of Trace Residues of the Herbicide Chlorsulfuron in Agricultural Runoff Water

Abstract A capillary column gas chromatographic method is described for determining parts-per-trillion (ppt) levels of chlorsulfuron in agricultural runoff water. The water sample is acidified with acetic acid and extracted with methylene chloride. The chlorsulfuron in the extract is derivatized to its monomethyl derivative. After Florisil column cleanup, the methylated chlorsulfuron is determined by electron-capture gas chromatography. Recovery of chlorsulfuron from fortified water samples is greater than 80%. Detection limit of the method is 25 ng chlorsulfuron/L water (25 ppt). There are 2 reaction sites on the chlorsulfuron molecule, both of which are susceptible to methylation leading to monomethyl chlorsulfuron and dimethyl chlorsulfuron. A procedure is described to methylate selectively the sulfonamide nitrogen of chlorsulfuron.</jats:p

PER-CUTANEOUS FNA BIOPSY WITH OPEN LYMPH NODE BIOPSY

Objective: To compare the efficacy of per cutaneous FNA biopsy with open lymph node biopsy. Setting: Nishtar Hospital, Multan. Sample size: 50 patients. Duration: One year. Results: Maximum numberof cases 35 (70%) were between the ages of 11-40 years. During this procedure adequate specimens were obtained from all cases for cytological interpretation and no complication was observed. Benign result in 30 cases while malignant disease was observed in 19 cases and an unsatisfactory result was observed in one case. Results of this study showed that tuberculosis is still a common disease in our population. Overall accuracy of FNAB cytology was 98% on comparison with histological diagnosis indicating the usefulnessof this technique. Conclusion: FNAB-C may be performed by clinician, pathologist or radiologist as an outpatient procedure. So along with other advantages it brings a new dimension of cooperation between the medical specialist, cytopathologist and radiologist in this era of emphasis on ambulatory care.</jats:p