Biomedical subjects

W Fiddler

Publications and source records attributed to W Fiddler.

63 records · Page 4Linked to original sources

PubMedDate not supplied

Comparison of three methods for determination of N-nitrosopyrrolidine in fried dry-cured bacon.

The recently developed Eastern Regional Research Center ( ERRC ) dry column chromatographic procedure for determining N-nitrosopyrrolidine (NPYR) in fried cure-pumped bacon was evaluated for its applicability to fried dry-cured bacon. The method was then compared with 2 established procedures for volatile nitrosamine analysis in cured meat products: the multidetection thermal energy analyzer (MD) method and the mineral oil distillation (MOD) screening procedure. No significant difference (P less than 0.05) in NPYR values was found between the ERRC and MD procedures, but significant differences were found between the ERRC and MOD procedures and between the MOD and MD procedures. No artifactual nitrosamine formation was found in the ERRC procedure, but significant amounts were found in samples analyzed by the MOD procedure. The ERRC method was demonstrated to be rugged and very rapid. It is proposed that the ERRC method replace the MOD method as the official screening procedure for NPYR in fried bacon.

Animals↗

PubMedDate not supplied

Dry column-thermal energy analyzer method for determining N-nitrosopyrrolidine in fried bacon: collaborative study.

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.

Animals↗

PubMedDate not supplied

Comparison of chemiluminescent and AOAC methods for determining nitrite in commercial cured meat products.

A chemiluminescent detector was used to measure nitrite in a variety of commercial cured meat products, using the AOAC sample preparation procedure, 24.041. A comparison of the NaNO2 values obtained by using sulfanilamide/N-(1-naphthyl)ethylenediamine (SAN/NED) reagent, sulfanilamide/1-naphthylamine reagent, and chemiluminescent detection (CLD) revealed no significant differences between the latter 2 detection methods. The AOAC SAN/NED reagent combination gave an average of 24.6% lower NaNO2 results than CLD. Examination of the sample preparation extraction and heating steps indicated that the procedure could not be made more rapid because of the need to destroy residual reductants and release "bound-complexed-reacted" nitrite from the meat samples.

Animals↗

PubMedDate not supplied

Supercritical fluid extraction of N-nitrosamines in hams processed in elastic rubber nettings.

A method for analysing N-nitrosamines in hams processed in elastic rubber nettings by supercritical fluid extraction (SFE) is described. The study was carried out with the prototype of a commercial extractor with a silica gel adsorption cartridge integrally attached to the variable restrictor. The SFE method was compared with a solid-phase extraction procedure currently used for ham analysis. Both methods used the same gas chromatographic-chemiluminescence detection conditions. No significant difference (p < 0.05) was found between results obtained with the 2 methods. Repeatability standard deviation of the SFE method was 1.7 ppb, with a coefficient of variation (CV) of 2.7%, compared with 2.2 ppb, with a CV of 3.5%, for solid-phase extraction. SFE permits minimal use of solvent and more rapid analysis of nitrosamines.

Animals↗

PubMedDate not supplied

Gas chromatographic/thermal energy analyzer method for N-nitrosodibenzylamine in hams processed in elastic rubber netting.

We previously described a solid-phase extraction (SPE) procedure for determining volatile nitrosamines in hams processed in elastic rubber nettings. This same procedure was found to successfully isolate N-nitrosodibenzylamine (NDBzA), a semivolatile nitrosamine. This nitrosamine may form as a result of the reformulated rubber now used in nettings. Reformulation became necessary because of the reported presence of N-nitrosodibutylamine in both the old nettings and on the exterior portion of commercial hams. After SPE, NDBzA was quantitated by using a gas chromatographic (GC) system interfaced to a nitrosamine-specific chemiluminescence detector [thermal energy analyzer (TEA)]. The GC system was equipped with a heated interface external to the TEA furnace to facilitate quantitation of NDBzA. With separation on a packed column, the method can be used to analyze 10 volatile nitrosamines and NDBzA. Repeatability of the method for NDBzA was found to be 2.1 ppb, and the coefficient of variation (CV) was 10.6%. Analysis of 18 commercial hams from 9 different producers, purchased from local retailers, indicated that 12 were positive for NDBzA (range, 2.6-128.5 ppb). NDBzA was confirmed by GC/mass spectrometry.

Animals↗

PubMedDate not supplied

Gas chromatographic/chemiluminescence detection (thermal energy analyzer-nitrogen mode) method for the determination of dibutylamine in hams.

A gas chromatographic (GC) procedure is described for the determination of dibutylamine (DBA) in ham at less than 1 ppm. Sample is extracted with 0.5N HCl, centrifuged, made basic, and then extracted with isopropyl alcohol. Final determination is by GC/thermal energy analysis in the nitrogen mode. Six replicate analyses of ham fortified with 0.5 ppm DBA gave a recovery of 90.2 +/- 3.4%. Over a range of 0.5 to 3.0 ppm DBA, the repeatability was 0.07 ppm, and the coefficient of variation was 6.07%. Limit of detection was 0.1 ppm. Effectiveness of the procedure was demonstrated on selected ham samples.

Animals↗

PubMedDate not supplied

Determination of extractable, apparent total N-nitroso compounds in cured-meat products.

The modification of a newly developed method for determination of apparent total N-nitroso compounds by chemical denitrosation and chemiluminescence detection of nitric oxide (thermal energy analysis) is described. The minimum level of reliable measurement was 0.1 ppm, and the repeatability of the method was 0.2 ppm, based on the response of N-nitrosoproline(NPro). Seventy-three samples of cured-meat products, including frankfurters, bacon, and ham, were examined; 50 samples contained less than 1 ppm. The largest amounts, up to 24.8 ppm, were detected in canned corned beef. This method has several advantages over other methods.

Animals↗

PubMedDate not supplied

Supercritical fluid extraction of volatile N-nitrosamines in fried bacon and its drippings: method comparison.

N-Nitrosopyrrolidine (NPYR) and N-nitrosodimethylamine (NDMA), known animal carcinogens, are consistently formed in bacon during frying. As a result, commercial bacon has been subject to regulatory monitoring and compliance for the past 20 years to ensure that N-nitrosamines do not exceed the 10 ppb volatile level. Currently, time-consuming distillation-solvent extraction and solid-phase extraction (SPE) methods are used for this purpose. With an emphasis on reducing solvent use, we investigated supercritical fluid extraction (SFE) using supercritical carbon dioxide (SC-CO2) for isolation of volatile nitrosamines common to fried bacon. Eighteen fried bacon samples were analyzed for NPYR and NDMA by SFE, SPE, mineral oil distillation (MOD), and low-temperature vacuum distillation (LTVD) methods, using the same gas chromatographic-chemiluminescence detection (thermal energy analyzer) conditions. The range of values for SFE was 0.7 to 20.2 ppb for NPYR and none detected (ND) to 2.4 ppb for NDMA. Analysis of variance of the NPYR data showed a significant difference (p < 0.05) between SFE and SPE results and significant differences between these and those obtained by MOD and LTVD. Overall, SFE was superior to the other methods with the highest recoveries, best repeatability, rapidity of analysis, and solvent-sparing characteristics. Similar results were obtained for SFE after comparison with distillation and SPE methods for determining the same nitrosamines in fried bacon drippings.

Analysis of Variance↗

PubMedDate not supplied

N-nitrosodibenzylamine in boneless hams processed in elastic rubber nettings.

Boneless hams processed in elastic rubber nettings contain high levels of nitrosamines in the outermost layer. The precursors of the nitrosamines are zinc dibutyl- or dibenzyldithlocarbamate used as a vulcanizing agent in the formulation of the rubber. The outermost layer from 59 commercial hams was analyzed for 11 volatile nitrosamines including N-nitrosodibutylamine (NDBA) and N-nitrosodibenzylamine (NDBzA). The principal nitrosamine, NDBzA, was detected in 32 (54%) ham samples at the 10-100 ppb range; it exceeded 100 ppb in 18 (30%) samples, with the highest at 512.2 ppb. No nitrosamine was detected in 7 of 59 ham samples. To determine the cause of the high NDBzA values, various types of unused nettings (from different manufacturers) accompanying the samples were analyzed for nitrosamines. No correlation was found between the NDBzA content of the hams and the nettings. The results suggest that the problem of nitrosamine formation in these products has not yet been resolved.

Animals↗