Simultaneous Determination of Multiple Tetracycline Residues in Milk Using Metal Chelate Affinity Chromatography

1993 ◽  
Vol 76 (2) ◽  
pp. 329-334 ◽  
Author(s):  
Mary C Carson
Keyword(s):  
Metal Chelate ◽  
Raw Milk ◽  
Good Precision ◽  
Milk Samples ◽  
Fortified Milk ◽  
On Line ◽  
Fast Flow ◽  
Tetracycline Residues ◽  
Metal Chelate Affinity Chromatography

Abstract A method was developed for the determination of 7 tetracyclines in milk. Raw milk samples are defatted, acidified, and centrifuged to remove proteins, and the tetracyclines are specifically absorbed from the milk by chelation with metal ions bound to small Chelating Sepharose Fast Flow columns. The tetracyclines are removed from these columns with EDTA-containing buffer, and the extracts are further cleaned up by centrifugal ultrafiltration. Finally, the extracts are concentrated and analyzed simultaneously by on-line concentration. This method has limits of detection for individual tetracyclines of <5 ng/mL and was validated with fortified milk samples at 15,30, and 60 ng/mL. Recoveries exceeded 60% for all tetracyclines at all levels, with good precision. The method was also tested on milk from cows dosed with each of the tetracyclines. Advantages of this method over existing methods include its sensitivity, minimal use of organic solvents, and speed; with an autosampler, at least 14 samples can be processed and analyzed in 1 day.

scholarly journals Simultaneous Determination of Multiple Tetracycline Residues in Milk by Metal Chelate Affinity Chromatography: Collaborative Study

1996 ◽  
Vol 79 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Mary C Carson ◽  
Wayne Breslyn ◽  
J Carmany ◽  
S Cross ◽  
W H Farrington ◽  
...  
Keyword(s):  
Metal Chelate ◽  
Collaborative Study ◽  
Raw Milk ◽  
Milk Samples ◽  
Relative Standard ◽  
Control Milk ◽  
Fast Flow ◽  
Tetracycline Residues ◽  
Liquid Chromatographic

Abstract To meet federal and state regulatory needs, a liquid chromatographic (LC) method with ultraviolet (UV) detection was developed for determination of 7 tetracyclines at 30 ng/mL in milk. Raw milk samples are defatted, acidified, and centrifuged to remove proteins, and tetracyclines are specifically absorbed from the milk by chelation with metal ions bound to small Chelating Sepharose Fast Flow columns. Tetracyclines are removed from these columns with EDTA-containing buffer, and extracts are further cleaned by ultrafiltration. Finally, extracts are concentrated and analyzed simultane ously by using on-line concentration. This method was validated in a collaborative study that involved 11 laboratories, including the authors’ laboratory. Each laboratory was asked to prepare and analyze known control and fortified milk samples, as well as 18 coded blind samples. Eight laboratories completed all analyses. Average interlaboratory recoveries for the known fortified samples ranged from 59% (methacycline at 15 ng/mL) to 78% (oxytetracy cline at 60 ng/mL). Average recovery for each of 7 residues at 30 ng/mL were between 60 and 110%, meeting single-residue guidelines for accuracy set by the U.S. Food and Drug Administration. Reproducibility relative standard deviation (RSDR) for the known fortified samples varied from 11 to 39%, with 6 of 7 residues at the 30 ng/mL level having RSDR values at or below 20%. Seven of 8 laboratories correctly identified blind control milk samples and all 28 residues present in blind samples. The metal chelate affinity—LC method for determination of multiple tetracycline residues in milk has been adopted first action by AOAC INTERNATIONAL.

Stability of Tetracycline Antibiotics in Raw Milk under Laboratory Storage Conditions

1999 ◽  
Vol 62 (5) ◽  
pp. 547-548 ◽  
Author(s):  
LYNDA V. PODHORNIAK ◽  
SHANITA LEAKE ◽  
FRANK J. SCHENCK
Keyword(s):  
Metal Chelate ◽  
Raw Milk ◽  
Storage Conditions ◽  
Screening Tests ◽  
Rapid Screening ◽  
Tetracycline Antibiotics ◽  
Milk Samples ◽  
Bulk Milk ◽  
Tetracycline Residues ◽  
Metal Chelate Affinity Chromatography

Raw milk samples collected from bulk milk tankers may be screened for the presence of tetracycline antibiotics using rapid screening tests. If tetracycline residues are detected, the milk may be shipped to a laboratory for high-pressure liquid chromatography (HPLC) analysis. Because the milk may be shipped on ice blocks, it is important to know whether tetracycline residues are stable at that temperature and for how long. Control raw milk samples fortified with 50 ppb each chlortetracycline, demeclocycline, methacycline hydrochloride, minocycline, oxytetracycline, and tetracycline were incubated at 4°C or 25°C, then analyzed using a metal chelate affinity chromatography extraction and HPLC. No loss of tetracycline was observed after 48 h of storage at 4°C or 24 h at 25°C. Losses ranging from 4 to 13% and 0 to 18% were noted after 72 h at 4°C and 48 h at 25°C, respectively.

scholarly journals HPLC-DAD multi-residue method for determination of florfenicol, penicillin and tetracycline residues in raw cow milk

2021 ◽  
Vol 2 (3) ◽  
pp. 01-08
Author(s):  
Ali Jaber ◽  
Zeinab Zahreddine ◽  
Simon Abou Haidar ◽  
Chadi Hosri ◽  
Ghassan Ibrahim ◽  
...  
Keyword(s):  
High Performance ◽  
Solid Phase ◽  
Raw Milk ◽  
Reversed Phase ◽  
Cow Milk ◽  
Antibiotic Residues ◽  
Milk Samples ◽  
Antibiotics Residues ◽  
Tetracycline Residues

The existence of antibiotic residues in edible products constitutes a health problem to the consumers. Reversed-phase high-performance liquid chromatography with diode array detection (HPLC–DAD) was optimized and validated for the simultaneous determination of florfenicol (FF), penicillin (PE), and tetracycline (TC) residues in dairy raw milk samples. The determination of these antibiotics was carried out on HP-ODS Hypersil C18 (5μm, 125*4 mm) column at a flow rate (1mL/min) and temperature (35 ⁰C). The extraction method includes deproteinization of the milk sample followed by a solid-phase extraction (SPE) clean-up. The method was validated according to the European Commission Decision 2002/657/EC and the International Conference of Harmonization Guidelines. The recoveries for the studied antibiotics ranged from 82–111.54 % making the method suitable for performing routine analysis. The proposed method was applied for the analysis of antibiotic residues in 50 dairy raw milk samples collected from many regions in Lebanon. The results showed the occurrence of these antibiotics residues in milk collected from different Lebanese regions. The numbers indicate that 22 % of milk samples were found to be positive for FF, 42 % for PE, and 28 % for TC residues.

scholarly journals Simultaneous Determination of C18 Fatty Acids in Milk by GC-MS

Separations ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 118
Author(s):  
Meiqing Chen ◽  
Yangdong Zhang ◽  
Fengen Wang ◽  
Nan Zheng ◽  
Jiaqi Wang
Keyword(s):  
Fatty Acids ◽  
High Sensitivity ◽  
Raw Milk ◽  
Uht Milk ◽  
Milk Samples ◽  
Accuracy And Precision ◽  
Different Temperatures ◽  
Chromatographic Resolution ◽  
Commercial Milk

The determination of C18 fatty acids (FAs) is a key and difficult aspect in FA profiling, and a qualified method with good chromatographic separation and high sensitivity, as well as easy methylation, is required. A GC-MS method was established to simultaneously determine C18 FAs in milk. To simplify the methylation protocol for milk samples, besides a base-catalyzation methylation (50 °C for 20 min), the necessity of an additional acid-catalyzation was also studied using different temperatures (60 °C, 70 °C, 80 °C, and 90 °C) and durations (90 min and 150 min). The results showed that the chromatographic resolution was improved, although three co-eluted peaks existed. The base-catalyzation was sufficient, and an additional acid-catalyzation was not necessary. The proposed method was validated with good sensitivity, linearity, accuracy, and precision, and then applied in determining C18 FAs in 20 raw milk and 30 commercial milk samples. UHT milk presented a different profile of C18 FAs from raw milk and PAS milk samples, which indicated that excessive heating could change the profile. Overall, the proposed method is a high-throughput and competent approach for the determination of C18 FAs in milk, and which presents an improvement in chromatographic resolution and sensitivity, as well as a simplification of methylation.

Determination of Viable Bacterial Populations in Raw Milk within 20 Minutes by Using a Direct Epifluorescent Filter Technique

1997 ◽  
Vol 60 (7) ◽  
pp. 874-876 ◽  
Author(s):  
CLAUDE P. CHAMPAGNE ◽  
NANCY J. GARDNER ◽  
JULIE FONTAINE ◽  
JACQUES RICHARD
Keyword(s):  
Raw Milk ◽  
Plate Count ◽  
Bacterial Populations ◽  
Filter Technique ◽  
Milk Samples ◽  
Standard Plate ◽  
Plate Counts ◽  
Direct Epifluorescent Filter Technique ◽  
Triton X

The results from a shortened procedure for the direct epifluorescent filter technique (DEFT) determination of viable bacterial populations in raw milk were compared to standard plate counts. Shortening the prefiltration trypsin-Triton X-100 incubation period from 10 to 3 min enabled the completion of the analysis within 20 min. The short DEFT method results had a correlation coefficient (r) of 0.81 with plate counts. With respect to precision, the average difference between values of duplicate plate count analyses was 0.16 log units; that of the short DEFT was 0.14 log units. The slopes of the regressions equations were less than 1, indicating that a direct correlation is not achieved. Short DEFT values were 0.17 log units higher than those of plate counts on milk samples containing less than 10,000 CFU/ml. For milk samples containing counts over 10,000 CFU/ml, short DEFT values averaged only 0.05 log units above plate count readings. Daily preparation of the stain appears unnecessary since acridine orange solutions stored for up to 2 days at 4°C did not produce results significantly (P > 0.05) different from those obtained with fresh solutions. The short DEFT method has potential for the assessment of the bacteriological quality of raw milk in tanker deliveries.

scholarly journals Determination of Four Fluoroquinolones in Milk by Liquid Chromatography

1997 ◽  
Vol 80 (5) ◽  
pp. 982-987 ◽  
Author(s):  
José E Roybal ◽  
Allen P Pfenning ◽  
Sherri B Turnipseed ◽  
Calvin C Walker ◽  
Jeffrey A Hurlbut
Keyword(s):  
Fluorescence Detection ◽  
Solid Phase ◽  
Raw Milk ◽  
Extraction Column ◽  
Isocratic Elution ◽  
Standard Curve ◽  
Milk Samples ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method with fluorescence detection is presented for the analysis of 4 fluoroquinolones; enrofloxacin (ENRO), ciprofloxacin (CIPRO), sarafloxacin (SARA), and difloxacin (DIFLX) in milk. The procedure consists of extraction of milk with acidified ethanol, isolation and retention on a cation exchange solid-phase extraction column, elution with basic methanol, and LC analysis with fluorescence detection. LC analysis is performed by isocratic elution using an acetonitrile-2% acetic acid (15 + 85) mobile phase and an Inertsil phenyl column with fluorescence detection at excitation and emission wavelengths of 278 and 450 nm, respectively. A target level of 10 ppb for each of the 4 fluoroquinolones has been established for this method. Average recovery from fortified raw milk samples (5-100 ppb each) based on a 5-point standard curve calculation was 70-90%, with relative standard deviations of <15%.

scholarly journals Physical and microbial qualities of raw milk collected from Bangladesh Agricultural University dairy farm and the surrounding villages

1970 ◽  
Vol 6 (2) ◽  
pp. 217-221 ◽  
Author(s):  
MTG Khan ◽  
MA Zinnah ◽  
MP Siddique ◽  
MHA Rashid ◽  
MA Islam ◽  
...  
Keyword(s):  
Microbiological Quality ◽  
Dairy Farm ◽  
Raw Milk ◽  
Viable Count ◽  
Physical Parameters ◽  
Total Viable Count ◽  
Coliform Count ◽  
Milk Samples

The present study was undertaken with the aim of investigating the physical parameters (e.g. organoleptic and specific gravity of raw milk) and also to study the microbiological quality of raw milk (total viable count, Coliform count and Staphylococcal count) from different villages and Bangladesh Agricultural University (BAU) Dairy Farm of Mymensingh District of Bangladesh, during the period from July to November 2007. A total number of 100 raw milk samples were collected at morning and evening from BAU dairy farm and surrounding four villages of BAU campus. The organoleptic and bacteriological qualities of each sample were analyzed. The organoleptic examination included taste panel score to assess consumer's acceptance and the bacteriological analysis comprised enumeration of total viable count (TVC), total colifrom count (TCC) and total staphylococcal count (TSC) for the determination of sanitary quality. The organoleptic quality of the milk samples is more or less same except the Churkhai milk samples which had flat taste (in 16% milk sample). The average values of TVC/ml were log 5.920, 5.934, 6.007, 6.075 and 6.127 for BAU Dairy Farm, Boira, Shutiakhali, Churkahai and Paglabazar respectively; coliform count were log 2.501, 2.522, 2.550, 2.620 and 2.619 respectively; staphylococcal count were log 2.832, 2.812, 2.866, 2.931 and 2.988 respectively. So, it may be concluded that the raw milk samples of BAU Dairy Farm were superior to others collected from the selected villages which may be due to maintaining better hygienic condition. Key words: Raw milk, physical and microbial quality   doi: 10.3329/bjvm.v6i2.2339 Bangl. J. Vet. Med. (2008). 6 (2): 217-221

Application of a microbial sensor for determination of short-chain fatty acids in raw milk samples

1992 ◽  
Vol 195 (1) ◽  
pp. 1-2 ◽  
Author(s):  
Hiroyuki Ukeda ◽  
Gotthold Wagner ◽  
G�nther Weis ◽  
Manfred Miller ◽  
Henning Klostermeyer ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Raw Milk ◽  
Short Chain Fatty Acids ◽  
Short Chain ◽  
Milk Samples ◽  
Microbial Sensor ◽  
Chain Fatty Acids
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