Collaborative Study of a Colorimetric Determination of Nitrate in Tobacco
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Abstract A colorimetric method for determining water-soluble nitrate in tobacco was studied by 14 laboratories on eight Burley and two cigar filler tobacco samples with nitrate levels of 0.5–2.4%. In the method, ground tobacco is extracted with water and filtered, and an aliquot is then treated with 2,4-xylenol in sulfuric acid; then the resulting 6-nitro-2,4-xylenol is removed by distillation and measured spectrophotometrically at 450 µm. Results show that, althoughthe precision standard deviation among laboratories is generally acceptable, the systematic error standard deviation is unacceptably high. This study will be continued.
1974 ◽
Vol 57
(2)
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pp. 373-378
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1990 ◽
Vol 73
(1)
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pp. 54-57
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1991 ◽
Vol 74
(1)
◽
pp. 22-26
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