Determination of nitroaromatics in biosludges with a gas chromatograph/thermal energy analyzer

1983 ◽  
Vol 55 (6) ◽  
pp. 889-892 ◽  
Author(s):  
John H. Phillips ◽  
Robert J. Coraor ◽  
Steven R. Prescott
Keyword(s):  
Thermal Energy ◽  
Energy Analyzer ◽  
Gas Chromatograph

Determination of Nitrate in Dried Foods by Gas Chromatography-Thermal Energy Analyzer

1985 ◽  
Vol 68 (1) ◽  
pp. 41-43
Author(s):  
Holly D Ross ◽  
Joseph H Hotchkiss
Keyword(s):  
Gas Chromatography ◽  
Ethyl Acetate ◽  
Thermal Energy ◽  
Energy Analyzer ◽  
Gas Chromatograph ◽  
Coefficients Of Variation ◽  
Dry Milk ◽  
Nonfat Dry Milk ◽  
Dried Foods

Abstract The method described for determining N03~ in dried foods is based on extraction of N03~ from the sample with subsequent nitration of benzene. The nitrobenzene is extracted with ethyl acetate, analyzed by using a gas chromatograph-thermal energy analyzer (GC-TEA), and quantitated against a nitrobenzene standard. Sensitivity is 100-200 μg/ kg. Coefficients of variation for analyses of dried foods were 3-13%. Recovery of N03" from nonfat dry milk spiked at 10 mg/kg averaged 100%.

Determination of N-Nitrosodimethylamine Levels in Some Canadian 2,4-D Amine Formulations

1987 ◽  
Vol 70 (1) ◽  
pp. 49-51
Author(s):  
Ralph W Hindle ◽  
J Fred Armstrong ◽  
Adeline A Peake
Keyword(s):  
Thermal Energy ◽  
Internal Standard ◽  
Packing Material ◽  
Dichlorophenoxyacetic Acid ◽  
Energy Analyzer ◽  
Gas Chromatograph ◽  
Canadian Market ◽  
Sample Aliquot ◽  
2,4 Dichlorophenoxyacetic Acid

Abstract Levels of/V-nitrosodimethylamine (NDMA) were determined in 112 samples of 2,4-dichlorophenoxyacetic acid, (2,4-D), formulated as the dimethylamine salt, collected over a 2 year period from products on the Canadian market. A sample aliquot is partitioned with dichloromethane, and the co-extracted dimethylamine is removed by cleanup on a silica gel column. The eluates containing NDMA are concentrated, an internal standard of /V-nitrosodipropylamine is added, and nitrosamine levels are determined using a gas chromatograph interfaced with a thermal energy analyzer. Recoveries of NDMA and N-nitrosodiethylamine spiked into samples were 103 ± 16 and 96.3 ± 9.8%, respectively. Of the 112 samples analyzed, 92 were below 1 part per million (ppm) relative to the amount of 2,4-D in the samples, 16 were between 1 and 5 ppm, and 4 were greater than 5 ppm. The gas chromatographic column used is compared to a conventional packing material for volatile nitrosamine analysis. Formation of NDMA during cleanup and analysis was shown not to occur.

Rapid and Simple Method for Isolation and Gas Chromatographic Determination of N-Nitrosodimethylamine in Dimethyldithiocarbamate Formulations

1989 ◽  
Vol 72 (4) ◽  
pp. 663-666
Author(s):  
Yuk Y Wigfield ◽  
Charles C Mclenaghan
Keyword(s):  
Thermal Energy ◽  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Energy Analyzer ◽  
Organic Fraction ◽  
Gas Chromatograph ◽  
Simple Method ◽  
Limit Of Quantitation ◽  
Extraction Tube

Abstract A rapid and simple method to isolate and determine JV-nitrosodimethylamine (NDMA) in formulations of ferbam or dibam has been developed. Depending on the type of formulation, the sample is extracted or diluted with water which is subsequently extracted with dichloromethane. NDMA is isolated by passing the organic fraction through a silica gel column and eluting the column with acetone. The acetone eluate is analyzed directly for NDMA by using a gas chromatograph connected to a thermal energy analyzer detector (GC/ TEA). The limit of detection (LOD) is 40 pg (0.04 ppm) and the limit of quantitation (LOQ) is 100 pg (0.1 ppm). The recovery range for this method is 85-112% for ferbam spiked at 0.33-0.75 ppm, and 91- 113% for dibam spiked at 0.32-1.09 ppm. Sixteen commercial samples of ferbam and 4 of dibam were analyzed; one ferbam sample contained 19.8 ppm NDMA while all others contained less than 1 ppm. Chem-Elut extraction tubes were found to generate trace quantities of nitrosamine from samples containing amine. If amine is absent, an extraction tube could be used in place of dichloromethane extraction to give similar values in recovery range, LOD, and LOQ.

Description of the thermal energy analyzer (TEA) for trace determination of volatile and nonvolatile N-nitroso compounds

1975 ◽  
Vol 47 (7) ◽  
pp. 1188-1191 ◽  
Author(s):  
David H. Fine ◽  
Firooz. Rufeh ◽  
David. Lieb ◽  
David P. Rounbehler
Keyword(s):  
Thermal Energy ◽  
Nitroso Compounds ◽  
Trace Determination ◽  
Energy Analyzer

Comparison of Three Methods for Determination of /V-Nitrosopyrrolidine in Fried Dry-Cured and Pump-Cured Bacon

1988 ◽  
Vol 71 (3) ◽  
pp. 504-508
Author(s):  
Anthony J Malanoski ◽  
Wertice J Smith ◽  
Thomas Phillipo
Keyword(s):  
Low Temperature ◽  
Thermal Energy ◽  
Validation Studies ◽  
Vacuum Distillation ◽  
Mineral Oil ◽  
Energy Analyzer ◽  
Coefficients Of Variation ◽  
The Individual

Abstract Three methods, the mineral oil distillation (MOD), the dry column (DC), and a low temperature vacuum distillation (LTVD), for the determination of iV-nitrosopyrrolidine in dry-cured and pump-cured bacon were compared. Each method uses the thermal energy analyzer for the determinative step. The coefficients of variation for repeatability were 10.3% (MOD), 7.2% (DC), and 9.1% (LTVD) for the dry-cured bacon study and 8.7% (MOD), 8.5% (DC), and 7.1% (LTVD) for the pump-cured bacon study. The pooled coefficients of variation for between-method reproducibility were 11.8% for the drycured bacon and 10.8% for the pump-cured bacon. The pooled coefficients of variation for repeatability were 9.0% for the dry-cured bacon and 8.2% for the pump-cured bacon. These values compare favorably with the values from previous collaborative or validation studies of the individual methods, and the methods can be considered to be equivalent

Determination of /V-Nitrosodipropylamine in Trifluralin Emulsifiable Concentrates Using Minicolumn Cleanup and Gas Chromatography with Thermal Energy Analyzer

1988 ◽  
Vol 71 (2) ◽  
pp. 333-336
Author(s):  
Dave Wotherspoon ◽  
Ralph Hindle
Keyword(s):  
Gas Chromatography ◽  
Thermal Energy ◽  
Internal Standard ◽  
Energy Analyzer ◽  
Quick Method ◽  
Coefficients Of Variation ◽  
Significant Difference ◽  
Artifact Formation ◽  
And Control

Abstract A quick method for determining /V-nitrosodipropylamine (NDPA) levels in trifluralin emulsifiable concentrate formulations is described. At least 18 samples can be analyzed at one time in a minimum of fumehood space, with up to 90% savings on solvents and materials. A sample aliquot is mixed with a solution containing nitrosamine recovery standards, and nitrosamines are separated by minicolumn cleanup. Internal standard is added directly to the eluate containing the nitrosamines, and levels are determined by gas chromatography with thermal energy analyzer. Recoveries of spiked nitrosamines ranged from 98 to 102%. Coefficients of variation for samples containing 0.5 ppm NDPA are 13%. Minimum detectable limit, calculated as 3 times the noise, is 0.06 ppm. Comparison with the method formerly used by this laboratory shows no significant difference in the analytical results at 95% confidence limits, and control experiments were performed to ensure that there was no artifact formation of NDPA.

scholarly journals Determination of Diethanolamine in Shampoo Products Containing Fatty Acid Diethanolamides by Liquid Chromatography with a Thermal Energy Analyzer

2005 ◽  
Vol 88 (2) ◽  
pp. 592-594 ◽  
Author(s):  
Hardy J Chou
Keyword(s):  
Acetic Acid ◽  
Liquid Chromatography ◽  
Fatty Acid ◽  
Thermal Energy ◽  
Sodium Nitrite ◽  
Room Temperature ◽  
Energy Analyzer

Abstract A liquid chromatography (LC) method using a thermal energy analyzer (TEA) is described for the determination of diethanolamine (DEA) in shampoo products containing fatty acid diethanolamides. DEA was converted to N-nitrosodiethanolamine (NDELA) by dissolving a portion of the product in 6M acetic acid and mixing with sodium nitrite for 1 h at room temperature. The reaction mixture was dried, dissolved in acetone, and analyzed for NDELA by LC-TEA. The recovery of DEA from 2 shampoo products at fortification levels of 25, 250, and 1000 ppm ranged from 70 to 105%. Twenty shampoo products were analyzed by this method, and 19 were found to contain DEA at levels ranging from 140 to 15 200 ppm.

Determination of N-Nitrosodimethylamine in Nonfat Dry Milk: Collaborative Study

1984 ◽  
Vol 67 (2) ◽  
pp. 232-236
Author(s):  
Nrisinha P Sen ◽  
Stephen Seaman ◽  
K Karpinsky ◽  
◽  
M Castegnaro ◽  
...  
Keyword(s):  
Thermal Energy ◽  
Collaborative Study ◽  
Sulfamic Acid ◽  
Complete Data ◽  
Energy Analyzer ◽  
Coefficients Of Variation ◽  
Dry Milk ◽  
Repeatability And Reproducibility ◽  
Nonfat Dry Milk

Abstract Ten laboratories participated in a collaborative study of a method for the determination of JV-nitrosodimethylamine (NDMA) in nonfat dry milk. NDMA is eluted with dichloromethane from a mixture of Celite, acidic sulfamic acid, and nonfat dry milk (all packed in a chromatography column), concentrated in a Kuderna-Danish concentrator, and finally analyzed by a GC-thermal energy analyzer technique. Ten samples were studied: 6 were naturally contaminated (NDMA levels 0.38- 3.56 ppb) and 4 were spiked with known levels (0.96 and 3.2 ppb) of NDMA. The coefficients of variation (CV) of the complete data for the naturally contaminated samples (excluding the 2 samples containing the lowest levels) were 8.5% and 22.5% for repeatability and reproducibility, respectively. The corresponding CVs for the spiked samples were 14.4% and 20.4%, respectively. The percent recoveries of the added NDMA in the spiked samples (at the 2 levels indicated above) were 101.6 ± 3.2 (omitting 1 outlier) and 95 ∓ 2.1, respectively. The method has been adopted official first action.

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