[' ', '~', '25', 'Following', 'the', 'extraction,', 'the', 'mixture', 'was', 'filtered', 'through', 'twe', 'Whatman', 'Glass', 'Microfibre', 'filter', 'pads', 'with', 'suction', 'into', 'a', '125-mL', 'filtering', 'flask.', 'The', 'filtercake', 'was', 'rinsed', 'three', 'times', '(approximately', '20', 'mL', 'each)', 'with', '70%', 'methanol.', 'The', 'filtercake', 'was', 'placed', 'into', 'a', '300-mL', 'double', 'thickness,', 'distilling', 'flask', 'and', 'analyzed', 'for', 'MH.', '™', '-', 'The', 'filtrate', 'was', 'transferred', 'into', 'a', '300-mL', 'double', 'thickness', 'dis', '.-', 'tilling', 'flask.', 'The', 'filtering', 'flasks', 'were', 'rinsed', 'three', 'times', 'with', 'ca', '20', 'mL', 'of', 'the', '70%', 'methanol', 'and', 'the', 'washes', 'added', 'to', 'the', 'distilling', 'flask.', 'The', 'filtrate', 'was', 'concentrated', 'to', 'a', 'volume', 'of', '15', 'mL', 'by', 'use', 'of', 'a', 'hot', 'water', 'bath', '(75', 'C)', 'and', 'air', 'stream', 'and', 'MH', 'determined.', 'Two-gram', 'samples', 'of', 'the', 'cured', 'tobacco', 'from', 'the', 'last', 'harvest', 'were', 'bores', 'extracted', 'with', '70%', 'methanol', 'and', 'subjected', 'to', 'the', 'same', 'procedure', 'as', 't', 'J', 'p', 'green', 'samples.', 'MH', 'residues', 'present', 'in', 'the', 'washoff', 'water', 'collected', 'in', 'the', 'greenhouse', 'study', 'were', 'also', 'determined.', 'Total', 'MH', 'was', 'determined', 'on', 'the', 'same', 'tissue', 'that', 'was', 'subjected', 'to', 'the', 'extraction', 'method', 'described', 'for', 'separating', 'free', 'and', 'bound', 'fractions.', 'Standard', 'curves', 'for', 'each', 'fraction', 'were', 'obtained', 'by', 'spiking', 'samples', 'of', 'MH-free', 'tobacco', 'with', 'known', 'amounts', 'of', 'MH', 'in', 'the', 'concentration', 'rate', 'that', 'the', 'unknown', 'samples', 'were', 'expected', 'to', 'fall.', 'The', 'curves', 'were', 'ficcer', '|', 'by', 'regresssion', 'analysis.', 'Correlation', 'coefficients', 'of', '0.96', 'cro', 'O.8%', 'were', '_', 'obtained', 'over', 'the', 'range', 'of', 'curves', 'prepared.', 'MH', 'residues', 'for', 'green', 'and', 'cured', 'leaf', 'were', 'based', 'on', 'a', 'moisture', 'content', 'of', '13%.', 'All', 'MH', 'values', 'were', 'transformed', 'to', 'natural', 'logarithms', 'for', 'statistical', 'analysis', 'to', 'stabilize', 'the', 'error', 'terms', 'associared', 'with', 'each', 'observation.', 'Analyses', 'of', 'variance', 'and', 'correlation', 'analyses', 'were', 'Peon', 'og', 'performed', 'on', 'the', 'transformed', 'data.', 'SOb¢', ' ']