Rapid Instrumental Fat Determination

1970 ◽  
Vol 53 (5) ◽  
pp. 1080-1081
Author(s):  
A J Malanoski ◽  
E L Greenfield
Keyword(s):  
Specific Gravity ◽  
Sample Preparation ◽  
Screening Tool ◽  
Automatic Computation ◽  
Automated Method ◽  
Aoac Method ◽  
No Sample Preparation ◽  
Plant Control

Abstract The Digital Fat Controller was evaluated for use in plant control and as a screening tool. The determination of fat by the Digital Fat Controller utilizes specific gravity with automatic computation and a “nixie” tube readout. No sample preparation is required and an analysis can be completed in 30–60 sec. Fiftysix samples were analyzed by both the automated method and the official AOAC method.

Extraction of Lipids from Raw Beef Lean by Using Various Solvent Systems

1967 ◽  
Vol 50 (2) ◽  
pp. 250-255 ◽  
Author(s):  
Susie N Hagan ◽  
Elizabeth W Murphy ◽  
Lydia M Shelley
Keyword(s):  
Sample Preparation ◽  
Drying Method ◽  
Preparation Methods ◽  
Drying Procedures ◽  
Aoac Method ◽  
Solvent Systems ◽  
Total Fat ◽  
Layer Chromatography ◽  
Chloroform Methanol

Abstract Study shows that chloroform-methanol extraction to remove lipids from beef yielded percentages of total fat equal to or greater than those obtained by the AOAC method. The ratio of phospholipid to triglyceride was always higher in the chloroform-methanol extracted samples. Six extraction methodsolvent system combinations, three drying procedures, and two sample preparation methods were compared. Tlie extracted lipids were separated by thin layer chromatography. The ratio of phospholipid to triglyceride was calculated after the spectrophotometric determination of the ester groups present. Acid-hydrolysis-Rohrig gave the lowest yield of total lipid and of phospholipid. Sample preparation method or drying method caused few significant dif. ferenccs in the proportions of total solids and of total lipids in the beef cuts analyzed

Automated Fluorometric Method for the Determination of Total Vitamin C in Food Products

1976 ◽  
Vol 59 (6) ◽  
pp. 1244-1250 ◽  
Author(s):  
Ram B Roy ◽  
Aldo Conetta ◽  
Jerry Salpeter
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Dehydroascorbic Acid ◽  
Food Products ◽  
Total Vitamin ◽  
Automated Method ◽  
Highly Sensitive ◽  
Aoac Method ◽  
Analytical System

Abstract A specific microfluorometric method for the determination of ascorbic acid, dehydroascorbic acid, and total vitamin C in food products has been automated. The procedure developed is an adaptation of the official AOAC method (secs. 43.056–43.062), except that N-bromosuccinimide is used instead of Norit to oxidize vitamin C. Ascorbic acid is selectively oxidized by N-bromosuccinimide before other interfering substances that may be present, so this method is a highly sensitive and specific technique with extensive applicability. The proposed automated method is simple, rapid, reliable, and sufficiently sensitive to analyze as little as 2 × 10−3 to 0.1 mg ascorbic acid/ml. Analytical results obtained for ascorbic acid, dehydroascorbic acid, and total vitamin C in a wide variety of food products are reported. The analytical system developed has the capability of analyzing 50 samples/hr.

scholarly journals Application of Sparging to the Automated Ion Selective Electrode Determination of Kjeldahl Nitrogen

1980 ◽  
Vol 63 (4) ◽  
pp. 931-936
Author(s):  
Ram B Roy ◽  
John Jansen ◽  
Michael Sahn
Keyword(s):  
Ion Selective Electrode ◽  
Selective Electrode ◽  
Ammonia Sensing ◽  
Automated Method ◽  
Significant Difference ◽  
Naoh Solution ◽  
Kjeldahl Digestion ◽  
Aoac Method ◽  
Kjeldahl Nitrogen

Abstract An automated method has been developed for the determination of total Kjeldahl nitrogen. Sample digests are mixed with a NaOH solution and allowed to make contact with air flowing at 1000 mL/min. The mixture enters the inlet of a heating bath maintained at 75°C. On exit, ammonia gas separates from a sparging vessel and is trapped as ammonium sulfate in a dilute H2SO4 solution. An aliquot of the acid solution is resampled and made alkaline to generate ammonia, which is measured by an ammonia sensing probe. A comparison of this procedure with AOAC method 7.025 shows that the procedure is accurate and that there is no statistically significant difference between them. This procedure introduces a new approach to eliminate the interfering species present in sample digests after Kjeldahl digestion for automated ion selective electrode measurements of ammonia. Thirty samples/h can be analyzed by this method.

Determination of Six Common Phthalate Plasticizers in Grain Neutral Spirits and Vodka

1995 ◽  
Vol 78 (3) ◽  
pp. 730-735 ◽  
Author(s):  
Jeffrey N Leebowitz ◽  
Rafael Sarmiento ◽  
Sumer M Dugar ◽  
Michael W Ethridge
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Liquid Chromatography ◽  
Sample Preparation ◽  
Sample Injection ◽  
Sample Enrichment ◽  
Injection Methods ◽  
No Sample Preparation ◽  
Direct Sample

Abstract Two direct sample injection methods using liquid chromatography (LC) and gas chromatography coupled with mass spectrometry (GC/MS) were used to determine phthalate residues in grain neutral spirits and vodka. Six reported phthalates were quantitated at concentrations as low as 20 μg/L (20 ppb) with no sample preparation or sample enrichment.

Determination of Copper in Alfalfa

1971 ◽  
Vol 54 (4) ◽  
pp. 951-952
Author(s):  
A Donald Baker
Keyword(s):  
Sample Preparation ◽  
Atomic Absorption ◽  
Hydrofluoric Acid ◽  
Atomic Absorption Spectrophotometry ◽  
Absorption Spectrophotometry ◽  
Dry Ashing ◽  
Wet Ashing ◽  
Aoac Method ◽  
Determination Of Copper

Abstract Copper in alfalfa is determined by atomic absorption spectrophotometry after dry-ashing or wet-ashing of the sample. The method is as precise as and considerably more rapid than the present AOAC method. The standard deviations of the method for wet- and dry-ashing sample preparation were 0.56 and 0.97%, respectively. Recovery of copper from spiked samples was 96—100%. Removal of silica by hydrofluoric acid fuming was not necessary.

Chemiluminescence Detection of Nitrite in Nonfat Dried Milk Powders

1982 ◽  
Vol 65 (3) ◽  
pp. 616-618
Author(s):  
Robert C Doerr ◽  
Robert A Gates ◽  
Walter Fiddler
Keyword(s):  
Statistical Analysis ◽  
Sample Preparation ◽  
Colorimetric Method ◽  
Chemiluminescence Detection ◽  
Milk Samples ◽  
Dry Milk ◽  
Nonfat Dry Milk ◽  
No Sample Preparation

Abstract Determination of nitrite in nonfat dry milk powders by chemiluminescence detection was compared with a colorimetric method specifying Griess reagents. The chemiluminescent technique requires no sample preparation, is free from apparent interferences, and is sensitive to 25 ppb nitrite. Statistical analysis shows no difference at P = 0.05 between the colorimetric and chemiluminescent methods, based on the analysis of 16 commercial nonfat dry milk samples.

Collaborative Study of an Automated Method for the Determination of Nitrogen in Meat Products

1974 ◽  
Vol 57 (4) ◽  
pp. 838-840
Author(s):  
Walter M Gantenbein ◽  
Jon L Schermerhorn ◽  
Elmer George
Keyword(s):  
Room Temperature ◽  
Collaborative Study ◽  
Meat Products ◽  
Automated System ◽  
Average Standard Deviation ◽  
Colorimetric Measurement ◽  
Automated Method ◽  
Average Coefficient ◽  
Aoac Method

Abstract An automated method for nitrogen in meat products was studied collaboratively. Samples were solubilized in sulfuric acid (1 + 1) , cooled to room temperature, and presented to an automated system. Digestion, dilution, and colorimetric measurement of the nitrogen were performed automatically. Samples were also analyzed by the official final action AOAC method, 24.010. Eight collaborators representing 6 laboratories participated in the study. Each participant analyzed 9 different samples in duplicate. Results of the study were satisfactory with an average range of 0.5% protein, average standard deviation of ±0.21%, and average coefficient of variation of 1.20%. The method was found to be as accurate as 24.010 and applicable to meat and meat products containing 0.8–4.0% nitrogen (5.0–25% protein). It has been adopted as official first action.

Automated Fluorometric Determination of Thiamine and Riboflavin in Infant Formulas

1979 ◽  
Vol 62 (3) ◽  
pp. 642-647
Author(s):  
Walter E Dunbar ◽  
Kenneth E Stevenson
Keyword(s):  
Sample Preparation ◽  
Infant Formulas ◽  
Fluorometric Method ◽  
Fluorometric Determination ◽  
Automated Method ◽  
Coefficients Of Variation ◽  
Manual Methods ◽  
The Mean ◽  
Better Than

Abstract Commercial infant formulas were analyzed simultaneously for thiamine and riboflavin by an automated fluorometric method and by the AOAC manual fluorometric methods. For 10 products, the mean thiamine and riboflavin results determined using the automated method ranged from 104 to 113% and 90 to 112%, respectively, of those by the AOAC manual methods. The coefficients of variation for thiamine and riboflavin ranged from 1.05 to 3.90% and 0.60 to 2.48%, respectively, for the automated method, and 1.48 to 3.86% and 0.69 to 10.9%, respectively, for the manual methods. Using the automated method, mean recoveries of thiamine and riboflavin added to samples were 103 and 104%, respectively. The automated method used a common sample preparation to determine both thiamine and riboflavin, and gave results equivalent to, or better than, those obtained by the manual methods.

Modification of AOAC Method for Determination of Soluble Solids in Tomato Products

1972 ◽  
Vol 55 (4) ◽  
pp. 809-810
Author(s):  
Frank C Lamb
Keyword(s):  
Sample Preparation ◽  
Excellent Agreement ◽  
Soluble Solids ◽  
Official Method ◽  
Aoac Method ◽  
Centrifugation Technique ◽  
Tomato Products ◽  
Good Agreement

Abstract The official first action method for soluble solids in tomato products, 32.008–32.010, was modified to permit the optional use of an ultracentrifuge to prepare samples for readings in a refractometer. Excellent agreement was obtained between the official method which specifies filtration and the centrifugation technique. Good agreement was also obtained between 2 laboratories using the centrifugation technique. The official method was modified to include the optional use of an ultracentrifuge for sample preparation.

Automated Determination of Thiamine (Vitamin B1) in Pharmaceutical Preparations

1971 ◽  
Vol 54 (5) ◽  
pp. 1164-1167
Author(s):  
Omer Pelletier ◽  
RenÉ Brassard
Keyword(s):  
Liver Extract ◽  
Vitamin B1 ◽  
Pharmaceutical Preparations ◽  
Manual Method ◽  
Automated Method ◽  
Thiamine Content ◽  
Aoac Method ◽  
Automated Determination

Abstract The chemical principles used for the determination of thiamine in pharmaceutical preparations by the official USP and AOAC methods were adapted to an automated flowthrough analyzer. The system could analyze 20 samples (including blanks) per hour. Thiamine extracts from 12 different multivitamin preparations were analyzed by one analyst on 5 different days by the automated method and the AOAC method. Both methods yielded comparable values for 10 of the preparations. The thiamine content of 2 preparations containing liver extract was found to be about 9% higher by the automated method than by the AOAC method. Further analysis of other samples of these 2 preparations containing liver extract showed that chromatography on Decalso did not change the results obtained by the automated method, but raised the results obtained by the manual method to a level comparable to the automated method. The AOAC method showed a tendency for a slightly higher reproducibility of assays.

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