Microparticle-enhanced nephelometric immunoassay for caseinomacropeptide in milk

1996 ◽  
Vol 63 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Christine Prin ◽  
Nezha El Bari ◽  
Paul Montagne ◽  
Marie-Louise Cuilliere ◽  
Marie-Christine Bene ◽  
...  
Keyword(s):  
Detection Limit ◽  
Low Temperature ◽  
Milk Sample ◽  
Bovine Milk ◽  
Polyclonal Antiserum ◽  
Whole Milk ◽  
One Step ◽  
Milk Storage ◽  
Slight Contamination

SummaryA microparticle-enhanced nephelometric immunoassay has been developed for the determination of caseinomacropeptide (CMP) in bovine milk. It is based on the nephelometric quantification of the competitive immunoagglutination of a microparticle–CMP conjugate with an anti-κ-casein (κ-CN) antiserum. This one step immunoassay was sensitive (detection limit in reaction mixture, 16μg/l), accurate (linear recovery of CMP in dilution overloading) and reproducible (CV 7–14% for within and between run precision). Because of the specificity of the polyclonal antiserum used, it was necessary to separate CMP from κ-CN by ultrafiltration before the quantification of bovine milk CMP. Under the conditions of milk ultrafiltration used, κ-CN was entirely retained (> 99·5%) but the concentration of CMP measured in milk ultrafiltrates was underestimated (by ∼25%) compared with its concentration in whole milk. Microparticle-enhanced nephelometric immunoassay of CMP, with a calibration range from 0·32 to 20 mg/1 for 20- fold diluted milk ultrafiltrate, allowed contamination of bovine milk by rennet whey as low as 5 ml/1 to be detected. Applied to ultrafiltrates from milk stored at 4 °C, this immunoassay also detected proteolysis of κ-CN not revealed by measurement of κ-CN concentration in milk. A statistical lower limit of 3·21 mg/1 was determined as the increase in CMP concentration in milk ultrafiltrates that indicated probable κ-CN proteolysis in the milk sample. Previously demonstrated to be an easy to perform method for assaying the main proteins of bovine milk, microparticle-enhanced nephelometric immunoassay thus also appeared to be appropriate to quantify CMP so as to detect slight contamination of milk by whey and to indicate the proteolysis of κ-CN during milk storage at low temperature.

scholarly journals Rapid Determination of Ampicillin in Bovine Milk by Liquid Chromatography with Fluorescence Detection

1997 ◽  
Vol 80 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Catharina Y W Ang ◽  
Luo Wenhong
Keyword(s):  
Fluorescence Detection ◽  
Rapid Determination ◽  
Bovine Milk ◽  
Skim Milk ◽  
Reversed Phase ◽  
Coefficients Of Variation ◽  
Whole Milk ◽  
Liquid Chromatographic ◽  
Clear Supernatant

Abstract A rapid and sensitive liquid chromatographic (LC) method was developed for the determination of am- picillin residues in raw bovine milk, processed skim milk, and pasteurized, homogenized whole milk with vitamin D. Milk samples were deprote- inized with trichloroacetic acid (TCA) and acetonitrile. After centrifugation, the clear supernatant was reacted with formaldehyde and TCA under heat. The major fluorescent derivative of ampicillin was then determined by reversed-phase LC with fluorescence detection. Average recoveries of ampicillin fortified at 5,10, and 20 ppb (ng/mL) were all >85% with coefficients of variation <10%. Limits of detection ranged from 0.31 to 0.51 ppb and limits of quantitation, from 0.66 to 1.2 ppb. After appropriate validation, this method should be suitable for rapid analysis of milk for ampicillin residues at the tolerance level of 10 ppb.

scholarly journals Photoinduced triplet-state electron transfer of platinum porphyrin: a one-step direct method for sensing iodide with an unprecedented detection limit

2015 ◽  
Vol 3 (13) ◽  
pp. 6733-6738 ◽  
Author(s):  
Dilshad Masih ◽  
Shawkat M. Aly ◽  
Erkki Alarousu ◽  
Omar F. Mohammed
Keyword(s):  
Electron Transfer ◽  
Detection Limit ◽  
Triplet State ◽  
Direct Method ◽  
Economical Method ◽  
State Electron ◽  
One Step ◽  
Platinum Porphyrin ◽  
First Time

Herein, we report for the first time the photoinduced triplet-state electron transfer of Pt(ii)TMPyP as an easy, rapid, environmentally friendly, ultra-sensitive and economical method for the determination of iodide in the aqueous phase.

Determination of dehydroepiandrosterone sulfate in plasma by a one-step enzyme immunoassay with a microtitre plate.

1985 ◽  
Vol 31 (11) ◽  
pp. 1876-1879 ◽  
Author(s):  
T K Dhar ◽  
C Müller ◽  
M Schöneshöfer
Keyword(s):  
Hydrogen Peroxide ◽  
Detection Limit ◽  
Enzyme Immunoassay ◽  
Cost Effective ◽  
Dehydroepiandrosterone Sulfate ◽  
Turnaround Time ◽  
Microtitre Plate ◽  
Standard Curve ◽  
One Step

Abstract We have developed a rapid and cost-effective enzyme immunoassay for dehydroepiandrosterone sulfate (DHEA-S) in plasma, performed with samples on a microtitre plate within 2.5 h. No extraction or centrifugation steps are involved. The 3-hemisuccinate of dehydroepiandrosterone is labeled with horseradish peroxidase, then mixed with hydrogen peroxide substrate in the presence of the chromogen, tetramethylbenzidine. The detection limit of the assay is 12.5 pg of DHEA-S per well. Intra- and interassay CVs at three steroid concentrations (12.8, 1.28, and 0.16 mumol/L) ranged from 2.3 to 5.4% and 6.1 to 8.4%, respectively. Results correlated well (r = 0.95) with those of a radioimmunoassay with iodinated DHEA-S. The turnaround time for 41 samples (in duplicate) is 2.5 h, which includes 2 h of incubation time. The sensitivity of this one-step version and the linearity of its standard curve are equivalent to those of a less practicable two-step version. This technique may replace coated-tube enzyme immunoassays for routine use.

scholarly journals An Immunoaffinity Column for the Determination of Peanut Protein in Chocolate

1999 ◽  
Vol 82 (3) ◽  
pp. 666-668 ◽  
Author(s):  
Harvey W Newsome ◽  
Michael Abbott
Keyword(s):  
Detection Limit ◽  
Immunoaffinity Chromatography ◽  
Polyclonal Antiserum ◽  
Peanut Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Immunoaffinity Column ◽  
Rabbit Polyclonal Antiserum ◽  
The Matrix ◽  
Direct Elisa

Abstract An immunoaffinity column was prepared from rabbit polyclonal antiserum for the determination of peanut protein from food matrixes. The anti-peanut immunoglobulin G was isolated from antiserum by affinity chromatography on a column coupled with peanut protein and then attached to an AminoLink gel. The column was applied to the determination of peanut protein in chocolate after extraction, immunoaffinity chromatography, and enzyme-linked immunosorbent assay (ELISA). Overall recoveries from chocolate spiked with 0.2–3.2 μg/g of peanut protein averaged 77% (range, 72–84%), and the minimum detection limit was 0.1 μg/g. Chromatography of extracts with the column improved detection limit and eliminated the matrix effect experienced with direct ELISA of chocolate extracts.

Chemiluminescent determination of xanthine oxidase activity in milk

1999 ◽  
Vol 66 (3) ◽  
pp. 441-448 ◽  
Author(s):  
STEFANO GIROTTI ◽  
SANDRO LODI ◽  
ELIDA FERRI ◽  
GRAZIELLA LASI ◽  
FABIANA FINI ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Enzyme Activity ◽  
Detection Limit ◽  
Sample Preparation ◽  
Xanthine Oxidase ◽  
Milk Sample ◽  
Uht Milk ◽  
Milk Samples ◽  
Chemiluminescent Method

A chemiluminescent method for determining xanthine oxidase (XOD) activity was developed and applied to the assay of milk enzyme activity using a photomultiplier luminometer. Various kinds of milk and cream samples were analysed for XOD content. In pasteurized milk, XOD activity depended on the fat content and in UHT milk it disappeared owing to the heat treatment. Milk sample preparation was very simple, requiring only homogenization at 40°C followed by a 1[ratio ]10 dilution with UHT (‘XOD-free’) milk. The assay was carried out at 25°C. The response obtained from XOD standard solutions in milk was linear from 0·1 to 500 enzyme units (U) l−1, but for the actual milk samples values ranged only from 1 to 135 U l−1. The detection limit at 2 SD was 0·1 U l−1 in milk, while in buffer it was 100 times lower. The intra-assay and interassay CV for XOD activity in milk were 6–12%.

scholarly journals Biosensor Immunoassay of Ivermectin in Bovine Milk

2002 ◽  
Vol 85 (4) ◽  
pp. 879-882 ◽  
Author(s):  
Jeanne V Samsonova ◽  
G Andrew Baxter ◽  
Steven R H Crooks ◽  
Christopher T Elliott
Keyword(s):  
Solid Phase ◽  
Bovine Milk ◽  
Optical Biosensor ◽  
Considerable Change ◽  
Extraction Techniques ◽  
Milk Samples ◽  
Assay Procedure ◽  
Working Day ◽  
Milk Storage

Abstract A rapid and sensitive biosensor immunoassay was developed for determination of ivermectin residues in bovine milk. A detection limit of 16.2 ng/mL was achieved. A Biacore optical biosensor based on surface plasmon resonance was used, and a range of extraction techniques was investigated. In the final assay procedure, ivermectin was extracted with acetonitrile followed by C8 solid-phase extraction cleanup. It was proven experimentally that 2 methods of milk storage, freezing or addition of mercury-containing compounds as preservatives, could be used without considerable change in detected concentrations (samples were fortified with ivermectin after storage). The average values for milk samples spiked at 100 and 50 ng/mL concentrations were 102.6 and 51.5 ng/mL, respectively. Extraction and analysis of 20 milk samples were performed within a single working day.

Colorimetric Determination of Fluoride in Drinking Groundwater using a Polymeric Zirconium Complex of 5-(2-Carboxyphenylazo)-8-Hydroxyquinoline

2013 ◽  
Vol 12 (7) ◽  
pp. 460-465
Author(s):  
Sameer Amereih ◽  
Zaher Barghouthi ◽  
Lamees Majjiad
Keyword(s):  
Drinking Water ◽  
Detection Limit ◽  
Complex Formation ◽  
Molar Absorptivity ◽  
Colorimetric Determination ◽  
Zirconium Complex ◽  
Reliable Determination ◽  
Percentage Recovery ◽  
Quantitation Limit

A sensitive colorimetric determination of fluoride in drinking water has been developed using a polymeric zirconium complex of 5-(2-Carboxyphenylazo)-8-Hydroxyquinoline as fluoride reagents. The method allowed a reliable determination of fluoride in range of (0.0-1.5) mg L-1. The molar absorptivity of the complex formation is 7695 ± 27 L mol-1 cm-1 at 460 nm. The sensitivity, detection limit, quantitation limit, and percentage recovery for 1.0 mg L-1 fluoride for the proposed method were found to be 0.353 ± 0.013 μg mL-1, 0.1 mg L-1, 0.3 mg L-1, and 101.7 ± 4.1, respectively.

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