Determination of solubility coefficients and sorption isotherms of gases in polymers by means of isothermal desorption with a chromatographic detection

Abstract A method using gel permeation and Florisil column chromatographic cleanup techniques is described for determination of residues of nonpolar organohalogen pesticides and pesticide alteration products in vegetable oils and their refinery by-products. Supplemental Florisil separation and alkali cleanup techniques are used to facilitate determinations. Residues are determined with a 63Ni electron capture gas chromatographic detection system used in conjunction with 3 different gas chromatographic columns. Residue identities are confirmed by gas chromatography-mass spectrometry. Recoveries of 7 organohalogen pesticides, ranging from 90 to 103%, were determined by the supplemental Florisil separation technique to augment previously reported recovery data determined for initial GPC and Florisil cleanup steps. Soybean, peanut, and cottonseed deodorizer distillates and crude and refined oil, as well as additional refinery by-products, were analyzed. Nine to 13 organohalogen residues ranging from 0.5 to 6.3 ppm were determined in the 2 soybean deodorizer distillate samples used to develop and test the method. Identities of residues present at ≥0.3 ppm were confirmed by gas chromatography-mass spectrometry. An intralaboratory trial of the method provided additional recovery and residue determination data as follows: Recoveries ranging from 102 to 116% were obtained for 4 pesticides added to peanut oil deodorizer distillate. Residues determined in 1 soybean deodorizer distillate sample supported previously obtained data for this sample.

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Thin Layer Chromatographic Detection and Spectrophotometric Determination of the Trisodium Salt of 1,3,6-PyrenetrisuIfonic Acid in D&C Green No. 8

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/67.4.762 ◽

1984 ◽

Vol 67 (4) ◽

pp. 762-763

Author(s):

Naomi Richfield-Fratz

Keyword(s):

Thin Layer ◽

Spectrophotometric Determination ◽

Chromatographic Method ◽

Chromatographic Detection ◽

Trisodium Salt

Abstract A thin layer chromatographic method is presented for separating the reaction by-product 1,3,6-pyrenetrisuIfonic acid (trisodium salt) (PTS) from D&C Green No. 8 (8-hydroxy-l,3,6-pyrenetrisulfonic acid). PTS is detected visually, extracted from the adsorbent, and determined spectrophotometrically. Recoveries of PTS added at 0.75-6.73% levels to 8-hydroxy-l,3,6-pyrenetrisuIfonic acid ranged from 80.0 to 94.8%.

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Determination of phosphorus requirements of Cowpea (Vigna unguiculata) in the acid soils of South-eastern Nigeria using sorption isotherms

Global Journal of Agricultural Sciences ◽

10.4314/gjass.v4i2.2262 ◽

2006 ◽

Vol 4 (2) ◽

Author(s):

VE Osodeke

Keyword(s):

Vigna Unguiculata ◽

Acid Soils ◽

Sorption Isotherms ◽

South Eastern ◽

Phosphorus Requirements

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Rapid Method of Determination of Sorption Isotherms and Water Apparent Diffusivity

Drying Technology ◽

10.1080/07373939608917193 ◽

1996 ◽

Vol 14 (9) ◽

pp. 2003-2023 ◽

Cited By ~ 3

Author(s):

J.M. Meot ◽

J.J. Bimbenet ◽

J. Abecassis

Keyword(s):

Rapid Method ◽

Sorption Isotherms ◽

Method Of Determination

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DETERMINATION OF l-HISTIDINE IN NANOGRAM AMOUNTS AND THE QUESTION OF ITS OCCURRENCE IN MAST CELLS

Journal of Histochemistry & Cytochemistry ◽

10.1177/20.11.917 ◽

1972 ◽

Vol 20 (11) ◽

pp. 917-922 ◽

Cited By ~ 4

Author(s):

DAVID I. WILKINSON ◽

DAVID GLICK

Keyword(s):

Mast Cells ◽

Rate Limiting Step ◽

Limiting Step ◽

Peritoneal Mast Cells ◽

Before And After ◽

Chromatographic Detection ◽

Rat Peritoneal Mast Cells ◽

Rate Limiting

In an attempt to clarify the question of whether histidine is stored in the mast cell for coversion to histamine or whether the rate of conversion is rapid enough to prevent accumulation of histidine so that the rate-limiting step is the histidine uptake, it was found that no histidine was demonstrable in rat peritoneal mast cells by either quantitative analysis or paper chromatographic detection. Microadaptation of Hassall's method, based on conversion of l-histidine by histidase to urocanic acid and measurement of the latter by its absorbance at 277 nm, was made to permit determination of histidine in nanogram amounts in the presence of histamine. This adaptation was found reliable when compared with the o-phthalaldehyde method in estimation of l-histidine in serum and in insulin hydrolysate, and then it was applied to analysis of mast cells before and after l-histidine uptake in vitro. The adaptation should be generally useful in microanalysis of l-histidine in histologically and cytologically defined samples.

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