Pork tissue samples

Fig. 5 Sample densitograms pork tissue samples fortified with 10 ppb sulfabromomethazine (SBZ) and either 0, 1.1, or 2.2 ppb of sulfamethazine (SMZ). Origin is at 0 mm, solvent front at 53 mm. (Reprinted from Ref. l)...

FIGURE 3.5 Sketch of the indirect competition FLISA protocol used for the multiplex determination of drugs in pork tissue samples. DEX, dexamethasone MPA, medroxyprogesterone acetate GM, gentamicin CZP, clonazepam CEF, ceftiofur and dBSA, denatured bovine serum albumin. (Reprinted with permission from Peng, C. et al. 2009. 

A simpler procedure consisting of protein precipitation using MeCN and TCA following formaldehyde derivatization was used for the determination of AMP in milk samples. The use of MeCN and TCA described in this method resulted in a clear supernatant and the highest recoveries (93% with CV of 6.1%). The derivatization reaction was done at 100°C for 30 min. The fluorescence of AMP derivatives was at least 20 times higher than that of AMO derivative thus, no preconcentration step was needed, resulting in the simplicity of this assay. A coextracted interfering unknown compound was observed at or near the retention time of the AMP derivative. This did not affect the accuracy (less than 10%) of the determination (74). A similar procedure was reported for beef, pork, chicken, and catfish tissue samples (75). 

Screening of ENRO, CIPRO, DAN, NOR, FLU, OXO, and NALA in pork muscle was based on HPTLC after the SPE procedure (195). Tissue samples were extracted with MeCN-NaOH, the supernatant dried, and the residues dissolved in dipotassium hydrogen phosphate buffer (pH 7.4) hexane was added. The aqueous phase was cleaned up using the SPE technique. After washing the cartridge, analytes were eluted with MeOH-ammonia solution (75 25). After the preparation step, extracts were spotted and eluted on silica gel plates. The plate is first inspected under UV illumination at 312 nm and then sprayed with terbium chloride. The method was validated at the levels of 15 yug/kg for ENRO, CPRO, DAN, and NOR and 5 yug/kg for FLU, 0X0, and NALA. 

A study was undertaken to evaluate the performance of the EZ-Screen Quik-C ard T est for sulfamethazine in pork urine, liver and muscle tissue (Table III). Initially, the EZ-Screen Quik Card was compared with the current USDA Sulfa-on-Site TLC method (14) for the screening of 569 pork urine samples at the plant level. Eighty-one urine samples were found positive by the EZ-Screen and only 36 by SOS. The corresponding 81 pork liver samples were then analyzed by both EZ-Screen and TLC. ... 

Sample fish and pork tissues Extraction SPE [19] CigDL ng/g,... 

Residues of TCs were quantified via the MCAC-HPLC method (26) in pork and chicken muscle tissue that had been previously screened with both a microbiological inhibition test using B. subtilis and an ELISA method. The correlation between the mean area of the inhibition zones and the DXC levels found in 28 samples by HPLC was 0.82 the correlation between the ELISA results and the DXC levels in the same samples was 0.73. The results indicated that an inhibition test was well suited to screen the mentioned samples for TCs residues. The authors found the more expensive ELISA screening test unnecessary, because only a minority of analyzed samples did not contain TCs. Confirmation with HPLC method was necessary because of the presence of some false-positive results. Moreover, the positive results from LC-fluorescence assay were confirmed using LC-MS-MS assay with electrospray ionization working in positive-ion mode (31). 

The column-switching system was applied to the determination of STR and DIHS in pork and bovine muscle and kidney. Perchloric acid was used to precipitate proteins and extract analytes from the tissue. The clear supernatant was further cleaned up by an offline SPE on a cation-exchange SPE column. After the washing of the cartridge with water, the analytes were eluted with phosphate buffer (pH 8.0) and diluted with HSA, perchloric acid, and water. The enrichment was achieved in the online mode. After loading the sample, the enrichment precolumn was flushed with HSA at pH 3.3 for 5 min. Using the ratio of MeCN to aqueous component of 83 17... 

The irradiation samples used were gelatin (Nitta Gelatin, G-0384K), pork, spongy bone, cortical bone, meniscus, fat, and bone marrow. These samples were used to simulate living tissue. The gelatin had dimensions 20 mm x 10 mm" X 20 mm and a concentration of 10 wt%. 

Thus, the various simulated tissues can be identified using the above-described frequency analysis. Fat and bone marrow had a low number of counts at the generated frequencies. Spongy bone had different peak frequencies from the other samples. Meniscus and cortical bone had few counts above a frequency of 50 kHz, although pork, meniscus, and cortical bone have similar peak frequencies. This indicates that tissue can be identified using the above-described frequency analysis. 

Beef, lamb, and pork muscles (m. longissimus dorsi) with attached adipose tissue were purchased from a local retailer. Adipose tissue was separated from muscle, and both were analyzed by SDE. Each sample was minced, and 100 g of either muscle or adipose tissue was placed in a 2-L round-bottomed flask, to which 750 mL of water was added. The samples were then extracted for 2 hr, using 30 mL of pentane/ether (9 1) as solvent. Two drops of silicone antifoaming agent were added to the meat samples. After the first extraction, each sample was extracted a second time, to determine whether any remained in the sample. The extracts were stored in a freezer overnight to remove water and concentrated to 0.2 mL. Methyl decanoate (500 ng) was added as an internal standard. Two replicates were performed for each extraction. A standard of pure (Z)-4-heptenal was also injected to determine its retention time and mass spectrum. 

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