Known Addition Procedure for Determining Fluoride in Feeds with an Ion-Specific Electrode

1974 ◽  
Vol 57 (3) ◽  
pp. 508-510 ◽  
Author(s):  
James R Melton ◽  
William L Hoover ◽  
Jo Lynn Ayers
Keyword(s):  
Ionic Strength ◽  
Solid State ◽  
Hydrochloric Acid ◽  
Addition Method ◽  
Citrate Buffer ◽  
Aoac Method ◽  
Low Levels ◽  
Fluoride Electrode ◽  
Feed Samples

Abstract A know addition method for determining low levels of fluoride in feeds with a solid-state fluoride electrode is described. The feed samples are reacted with hydrochloric acid, and a concentrated citrate buffer is added to maintain ionic strength and pH. The amount of fluoride in the sample is calculated from the change in potential after the addition of fluoride standard. Any interferences by ions commonly found in feeds are minimized by the known addition technique. The described method is rapid and precise, and results compare favorably with those from the AOAC method for fluoride, 25.029-25.035.

Determination of Iodide in Feeds and Plants by Ion-Selective Electrode Analysis

1971 ◽  
Vol 54 (4) ◽  
pp. 760-763
Author(s):  
William L Hoover ◽  
James R Melton ◽  
Peggy A Howard
Keyword(s):  
Ionic Strength ◽  
Solid State ◽  
Necessary Conditions ◽  
Ion Selective Electrode ◽  
Phosphate Solution ◽  
Selective Electrode ◽  
Aoac Method ◽  
Low Levels ◽  
High Concentrations

Abstract A method for determining low levels of iodide in feeds and plants is proposed. The samples are mixed with a 10% phosphate solution to maintain relatively constant ionic strength and pH and analyzed with a solid-state iodide electrode. Ashing is not required and there are no significant interferences by ions commonly found in feeds. The method is accurate in determining iodide content ranging from 10.0 ppm to high concentrations. Necessary conditions for storing and cleaning the electrodes are described. The proposed method is rapid and results compare favorably with AOAC method 7.091.

Three new staphylonuclear chloromolybdates : K6Mo3Cl12, (NH4)7Mo3Cl13,H2O, and Cs6Mo4Cl16

1965 ◽  
Vol 18 (3) ◽  
pp. 271 ◽  
Author(s):  
IR Anderson ◽  
JC Sheldon
Keyword(s):  
Solid State ◽  
Hydrochloric Acid ◽  
Absorption Spectra ◽  
Oxidation State ◽  
Chlorine Atom ◽  
Reducing Agents ◽  
Ammonium Salts ◽  
Chlorine Atoms ◽  
Regular Triangle ◽  
New Compounds

The new compounds, K6Mo3IICl12; (NH4)7Mo3IICl13.H2O; and Cs6Mo4Cl16 (containing molybdenum in oxidation state +2.5) have been precipitated by the appropriate cation from solutions of molybdenum(II) acetate in 12M hydrochloric acid. The absorption spectra of potassium and ammonium salts are similar in the solid state and solution. Since the compounds are strong reducing agents and short-lived in solution, their formulation as a staphylonuclear (i.e. metal-clustered) trimer or tetramer rests on their diamagnetism, stoicheiometry, and spectral similarities. It is proposed that the chloromolybdates adopt entirely novel, compact polymers by stacking the chlorine atoms into "close packed" layers. The Mo3Cl13 group consists of two layers of chlorine atoms (seven and six) generating three octahedral locations for the molybdenum atoms at the corners of a regular triangle. The Mo3Cl12 group is similar but deficient in one chlorine atom. The Mo4Cl16 group is related to Mo3Cl13 and consists of three layers of chlorine atoms (seven, six, and three) providing four octahedral locations for the molybdenum atoms at the corners of a tetrahedron.

Determination of Ochratoxin A in Feed by Immunoaffinity Cleanup and Liquid Chromatography

2013 ◽  
Vol 96 (3) ◽  
pp. 599-602 ◽  
Author(s):  
Ping Ding ◽  
Ziyou Mi ◽  
Yali Hou ◽  
Yigang He ◽  
Jianhua Xie
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Ochratoxin A ◽  
Cyanogen Bromide ◽  
Polyclonal Antibodies ◽  
Immunoaffinity Column ◽  
Low Levels ◽  
Sepharose 4B ◽  
Feed Samples

Abstract A method using LC was developed for determination of ochratoxin A (OTA) in feeds. The extracted samples were cleaned up by an immunoaffinity column prepared by covalently coupling polyclonal antibodies against OTA to cyanogen bromide-activated Sepharose 4B. The eluates were determined by LC with fluorescence detection. Recoveries of OTA from fortified samples of 1–10 μg/kg levels ranged from 84.3 to 90.0%, with CVs of 3.3–7.8%. The detection limit was 0.045 μg/kg based on an S/N of 3:1. A total of 65 feed samples were screened for OTA with the proposed method. The results showed that only nine samples were contaminated with OTAs at low levels. The presented method was successfully applied to quantify OTAs in real feed samples.

scholarly journals STUDIES ON THE FORMATION OF COLLAGEN

1958 ◽  
Vol 107 (2) ◽  
pp. 265-277 ◽  
Author(s):  
Jerome Gross
Keyword(s):  
Growth Rate ◽  
Weight Gain ◽  
Guinea Pigs ◽  
Caloric Intake ◽  
Neutral Salt ◽  
Salt Solutions ◽  
Citrate Buffer ◽  
Continuous Growth ◽  
Dermal Collagen ◽  
Low Levels

The total amount of neutral salt-extractible collagen in the skin of growing, suckling guinea pigs amounted to about 10 per cent of the total collagen of the dennis. This is roughly equivalent to a 1 to 2 day increment in dermal collagen incident to growth. Fourteen days of static weight maintained by limited caloric intake reduced the neutral salt-extractible collagen to very low levels. Following this period, 5 to 7 days of steady weight gain induced by ad lib. feeding was required to produce significant increases in this collagen fraction. Return to control levels occurred within 12 days of continuous growth. The amount of collagen extracted from the dermis of young guinea pigs with cold neutral salt solutions varied directly with growth rate (weight gain) and was greatly diminished after short periods of restricted caloric intake. Two days of fasting diminished the total extracted collagen by one-half. Three consecutive extractions with citrate buffer pH, 3.5, of the residues remaining after exhaustive saline extraction removed 40 per cent more collagen from the skins of actively growing animals than from those of animals fasted for 2 days. However, subsequent extraction of residues with dilute acetic acid equalized the total amount of collagen extracted at acid pH from the two groups. The viscosity of cold neutral extracts was unrelated to the concentrations of non-collagenous proteins and carbohydrates but varied directly with the collagen content.

Microbiological Assay of Oxytetracycline in Feed: Manual Turbidimetric Assay and Plate Assay

1973 ◽  
Vol 56 (1) ◽  
pp. 23-30
Author(s):  
Hussein S Ragheb ◽  
Anne M Cummings ◽  
Barbara M Browning
Keyword(s):  
Coefficient Of Variation ◽  
Microbiological Assay ◽  
Plate Method ◽  
Turbidimetric Method ◽  
Plate Assay ◽  
Coefficients Of Variation ◽  
Aoac Method ◽  
Turbidimetric Assay ◽  
Turbidimetric Analysis ◽  
Feed Samples

Abstract The useful range for manual turbidimetric analysis of Oxytetracycline (OTC), using K. pneumoniae, was between 0.04 and 0.08 μg/ml in the assay tubes. Laboratory-prepared feeds containing 43.5 and 86.5 g OTC.HCl/ton gave 90–98% recovery by the turbidimetric method and 104–116% by the AOAC method, 38.211–38.213. The coefficients of variation were 9.2–13.0 and 10.2–12.8%, respectively. Feeds containing 50 and 100 g OTC.HCl and neomyein sulfate/ton gave 77% of theory when analyzed turbidimetrically and 95% of theory by the plate method. The coefficient of variation for the turbidimetric method was about 16%, indicating unsatisfactory precision. At 200 g/ton theoretical concentration of each antibiotic, both methods agreed. Commercial premixes and finished feed samples gave almost the same results by both methods. The main advantage of the turbidimetric method over the plate assay is that results can be obtained the same day of analysis.

Spectrophotofluorometric Estimation of Low Levels of Diethylstilbestrol in Feedstuffs

1973 ◽  
Vol 56 (6) ◽  
pp. 1483-1488
Author(s):  
Marshall T Jeffus ◽  
Charles T Kenner
Keyword(s):  
Standard Deviation ◽  
Fluorescent Intensity ◽  
Low Levels ◽  
Feed Samples

Abstract A method for the determination of low levels of diethylstilbestrol in feedstuffs is described. Interfering feed extractives are removed by using a tripotassium phosphate-Celite column prior to irradiation. The dione produced by irradiation is oxidized to a phenanthrenediol and extracted into CH2CI2 for measurement of fluorescent intensity. The amount of diethylstilbestrol found in several feed samples ranged from 0 to 10 ng (0.0–0.5 ppb) with an average of 4 ng (0.2 ppb). Recoveries of 100 ng standards (equivalent to 5 ppb) added to the same samples averaged 91 ng with a standard deviation of 14 ng. Recoveries of 1000 ng standards (equivalent to 50 ppb) added to the same samples averaged 820 ng with a standard deviation of 14 ng. For 100 ng standards analyzed beginning with the irradiation procedure, the standard deviation was 5.6%, and for 1000 ng standards, the standard deviation was 2.8%.

scholarly journals Investigation of Assay Interference with Microbiological Determinations of Chlortetracycline in Feed Grade and Premix Samples

1997 ◽  
Vol 80 (2) ◽  
pp. 298-302 ◽  
Author(s):  
Gregory K Webster ◽  
Elizabeth S Luigs ◽  
Loretta A Hearne ◽  
Margaret Pomeroy ◽  
Linda A Panozzo ◽  
...  
Keyword(s):  
Peak Response ◽  
Microbiological Result ◽  
Commercial Feed ◽  
Aoac Method ◽  
Low Levels ◽  
Analytical Procedures ◽  
Liquid Chromatographic ◽  
Assay Interference

Abstract Studies were initiated to determine whether tetracycline components such as tetracycline and 4-epichlortetracycline present in commercial feed grade chlorteracycline (CTC) products interfere with AOAC Method 967.39. These investigations confirmed that the microbiological result for feed grade concentrates and premix products is not affected by the biomass matrix containing low levels of these other tetracycline components. Thus, the microbiological result can be directly correlated to the single CTC peak response in liquid chromatographic analytical procedures.

scholarly journals Counter-Current Leaching of Low-Grade Laterites with Hydrochloric Acid and Proposed Purification Options of Pregnant Solution

Minerals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 599 ◽  
Author(s):  
Christiana Mystrioti ◽  
Nymphodora Papassiopi ◽  
Anthimos Xenidis ◽  
Konstantinos Komnitsas
Keyword(s):  
Hydrochloric Acid ◽  
Current Mode ◽  
Leach Solution ◽  
Low Grade ◽  
Mode Of Operation ◽  
Oxidative Precipitation ◽  
Alkaline Earths ◽  
Low Levels ◽  
Counter Current ◽  
Mn Oxides

A hydrochloric acid hydrometallurgical process was evaluated for Ni and Co extraction from a low-grade saprolitic laterite. The main characteristics of the process were (i) the application of a counter-current mode of operation as the main leaching step (CCL), and (ii) the treatment of pregnant leach solution (PLS) with a series of simple precipitation steps. It was found that, during CCL, co-dissolution of Fe was maintained at very low levels, i.e., about 0.6%, which improved the effectiveness of the subsequent PLS purification step. The treatment of PLS involved an initial precipitation step for the removal of trivalent metals, Fe, Al, and Cr, using Mg(OH)2. The process steps that followed aimed at separating Ni and Co from Mn and the alkaline earths Mg and Ca, by a combination of repetitive oxidative precipitation and dissolution steps. Magnesium and calcium remained in the aqueous phase, Mn was removed as a solid residue of Mn(III)–Mn(IV) oxides, while Ni and Co were recovered as a separate aqueous stream. It was found that the overall Ni and Co recoveries were 40% and 38%, respectively. About 45% of Ni and 37% of Co remained in the leach residue, while 15% Ni and 20% Co were lost in the Mn oxides.

scholarly journals Fluoride Levels of Human Plasma and Breast Milk

2007 ◽  
Vol 01 (01) ◽  
pp. 021-024 ◽  
Author(s):  
Yağmur Şener ◽  
Gül Tosun ◽  
Firdevs Kahvecioğlu ◽  
Alparslan Gökalp ◽  
Hasan Koç
Keyword(s):  
Breast Milk ◽  
Fluoride Concentration ◽  
Hospital Setting ◽  
Significant Relation ◽  
Blood Samples ◽  
Milk Samples ◽  
Lactating Mothers ◽  
Primary Selection ◽  
Low Levels ◽  
Fluoride Electrode

ABSTRACTObjectives: The aim of this study was to determine the fluoride levels in breast milk and plasma of lactating mothers who regularly consumed drinking water with low levels of fluoride.Methods: One hundred twenty five healthy mothers aged between 20-30 years old who had given birth within 5-7 days were included in the study. Besides being otherwise healthy, the primary selection criteria stipulated the absence of fluoride supplement consumption one month before delivery. Approximately 5 ml breast milk and 5 ml blood samples were obtained from each participating mother at a hospital setting, where the mothers were scheduled for a regular hospital diet. The blood samples were centrifuged in fluoride-free heparinized polyethylene tubes and stored at -18oC until measurements were made. Breast milk samples were directly refrigerated as with blood samples until measurements. The fluoride concentrations of milk and blood samples were assessed using an ion-selective fluoride electrode combined with an ion analyzer.Results: The fluoride levels of the plasma and breast milk samples were measured as 0.017±0.011 ppm and 0.006±0.002 ppm, respectively. The fluoride concentration of plasma was significantly higher than that of breast milk (P<.01). Correlation analysis revealed a significant relation between the groups (P<.01).Conclusion: A limited level of fluoride transmission from plasma to breast milk was detected. Nevertheless, a significant correlation between the fluoride concentrations of breast milk and plasma was evident. (Eur J Dent 2007;1:21-24)

Reaction-Rate Method for Determining Protein Nitrogen in Grains and Feeds

1979 ◽  
Vol 62 (1) ◽  
pp. 23-28
Author(s):  
Michael S Mccracken ◽  
Howard V Malmstadt
Keyword(s):  
Quantitative Determination ◽  
Reaction Rate ◽  
Mixed Solution ◽  
Protein Nitrogen ◽  
Digestion Procedure ◽  
Relative Standard ◽  
Aoac Method ◽  
Rate Method ◽  
Feed Samples

Abstract In a new automated reaction-rate method for the quantitative determination of protein nitrogen in grains and feeds, the ammonia-sodium phenate-hypochlorite reaction is used for the reaction-rate determination. After samples are digested by the official AOAC block digestion procedure, automated instrumentation is used to precisely and rapidly combine the reactants and transfer the mixed solution to an automated spectrophotometer. The rate of formation of the indophenol during 15 sec at 635 nm is automatically determined and compared with rates obtained for nitrogen standards to determine the protein nitrogen content in the sample. Relative standard deviations of about 0.6% are obtained. Results for grain and feed samples are comparable to those obtained by the official AOAC method.

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