High Temperature Purge and Trap Procedure for Determining Seven Volatile N-Nitrosamines in Animal Feed, Using Gas Chromatography/Thermal Energy Analyzer

1984 ◽  
Vol 67 (3) ◽  
pp. 557-562
Author(s):  
Stanley M Billedeau ◽  
Harold C Thompson ◽  
Eugene B Hansen ◽  
Barbara J Miller
Keyword(s):  
Gas Chromatography ◽  
High Temperature ◽  
Thermal Energy ◽  
Animal Feed ◽  
Mineral Oil ◽  
Nitroso Compounds ◽  
Energy Analyzer ◽  
Purge And Trap ◽  
Multiple Sample ◽  
Feed Samples

Abstract A rapid and sensitive procedure is described for determining 4 N- nitrosodialkylamines (dimethyl, diethyl, dipropyl, and dibutyl) and the N-nitroso analogs of piperidine, pyrrolidine, and morpholine in animal feed. The volatile N-nitrosamines were isolated by using a modified high temperature purge and trap apparatus designed for multiple sample cleanup. The feed sample was mixed with mineral oil and a nitrosation inhibitor, and the N-nitrosamines were purged onto a ThermoSorb/N cartridge, eluted with acetone–dichloromethane (1 + 1), and determined by gas chromatography, using a thermal energy analyzer. The effects of purge rate, purge time, and temperature on recovery are discussed. Feed samples spiked with 10, 50, and 200 ppb of the 7 N-nitroso compounds yielded recoveries ranging from 70 to 97%, with precision ranging from 1.3 to 5.4% and minimum detectable levels in the low parts-per-billion range.

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.

Dry Column-Thermal Energy Analyzer Method for Determining N-Nitrosopyrrolidine in Fried Bacon: Collaborative Study

1984 ◽  
Vol 67 (3) ◽  
pp. 521-525
Author(s):  
Walter Fiddler ◽  
John W Pensabene ◽  
Robert A Gates ◽  
John G Phillips ◽  
◽  
...  
Keyword(s):  
Thermal Energy ◽  
Collaborative Study ◽  
Internal Standard ◽  
Mineral Oil ◽  
Energy Analyzer ◽  
High Group ◽  
Average Recovery ◽  
Column Method ◽  
Coefficients Of Variation ◽  
Repeatability And Reproducibility

Abstract A dry column method for isolating N-nitrosopyrrolidine (NPYR) from fried, cure-pumped bacon and detection by gas chromatography-thermal energy analyzer (TEA) was studied collaboratively. Testing the results obtained from 11 collaborators for homogeneous variances among samples resulted in splitting the nonzero samples into 2 groups of sample levels, each with similar variances. Outlying results were identified by AOAC-recommended procedures, and laboratories having outliers within a group were excluded. Results from the 9 collaborators remaining in the low group yielded coefficients of variation (CV) of 6.00% and 7.47% for repeatability and reproducibility, respectively, and the 8 collaborators remaining in the high group yielded CV values of 5.64% and 13.72%, respectively. An 85.2% overall average recovery of the N-nitrosoazetidine internal standard was obtained with an average laboratory CV of 10.5%. The method has been adopted official first action as an alternative to the mineral oil distillation-TEA screening procedure.

Confirmation of N-Nitrosodimethylamine and N-Nitrosopyrrolidine in Foods By Conversion to their Nitramines with Pentafluoroperoxybenzoic Acid

1984 ◽  
Vol 67 (4) ◽  
pp. 751-756
Author(s):  
Walter I Kimoto ◽  
Leonard S Silbert ◽  
Walter Fiddler
Keyword(s):  
Gas Chromatography ◽  
Electron Capture ◽  
Thermal Energy ◽  
Milk Powder ◽  
Energy Analyzer ◽  
Detection Level ◽  
Electron Capture Detectors

Abstract Amethod is presented, wherein concentrated dichloromethane extracts from malt, beer, and nonfat dried milk powder containing N-nitrosodimethylamine (NDMA), and fried dry-cured and pump-cured bacon containing NDMA and iV-nitrosopyrrolidine (NPYR) undergo 3N HC104- Celite microcolumn cleanup followed by peroxidation with pentafluoroperoxybenzoic acid, a stable solid peroxyacid, to N-nitrodimethylamine and N-nitropyrroIidine, as an aid to nitrosamine confirmation. The nitramine-containing solution underwent further cleanup with 6N HC104-Celite and acid alumina-6 % H2O microcolumns for subsequent analysis by gas chromatography interfaced with thermal energy analyzer and 63Ni electron capture detectors. With a 20 g sample, 1 ppb NDMA and 2.5 ppb NPYR could be confirmed by this method. The extract can be concentrated further before analysis, so the detection level can be reduced to <1 ppb NDMA and 1 ppb NPYR.

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