Automated Method for the Analysis of Riboflavin in Milk, with Application to Other Selected Foods

1974 ◽  
Vol 57 (5) ◽  
pp. 1085-1088
Author(s):  
James R Kirk
Keyword(s):  
Standard Deviation ◽  
Continuous Flow ◽  
Quantitative Method ◽  
Green Fluorescence ◽  
Internal Standards ◽  
Automated Method ◽  
Sodium Hydrosulfite ◽  
Automated Technique ◽  
Good Agreement

Abstract A continuous flow automated technique was developed for the determination of riboflavin in milk. The determination is based on the measurement of the natural yellow-green fluorescence of riboflavin at an excitation of 436 nm and emission of 510 nm. Blank values are determined for each sample after sodium hydrosulfite reduction of the riboflavin. Mean recovery and standard deviation for riboflavin in milk determined by the continuous flow procedure using internal standards were 9 7% and ± 2.42%, respectively. The recovery value was in good agreement with that determined using a manual procedure, while the standard deviation was 33% less than that found when using the manual procedure. The results from this study indicate that the continuous flow automated procedure for the determination of riboflavin in milk is a simple, quantitative method which eliminates many of the time-consuming analytical steps.

An Automated Method for the Determination of Serum Calcium with Glyoxal Bis (2-Hydroxyanil)

1967 ◽  
Vol 13 (6) ◽  
pp. 515-520 ◽  
Author(s):  
Genevieve Farese ◽  
Janice L Schmidt ◽  
Milton Mager
Keyword(s):  
Serum Calcium ◽  
Automated Analysis ◽  
Automated Method ◽  
Good Agreement

Abstract A completely automated analysis is described for the determination of serum calcium with glyoxal bis (2-hydroxyanil) solution (GBHA). The method is simple and precise, and the data obtained are in good agreement with results obtained by the manual GBHA procedure.

Automated Fluoride Ion Determination

1977 ◽  
Vol 14 (1-6) ◽  
pp. 269-274 ◽  
Author(s):  
David C. Cowell
Keyword(s):  
Continuous Flow ◽  
Ion Concentration ◽  
Fluoride Ion ◽  
Selective Electrode ◽  
Automated Method ◽  
Electrode Response ◽  
Kinetics Of ◽  
Fluoride Ion Selective Electrode ◽  
Flow Techniques

An automated method is described, using standard continuous flow techniques, for the determination of urine fluoride ion concentration using a fluoride ion selective electrode. It is shown that the kinetics of the electrode response to changes in fluoride ion can be used for the accurate measurement of fluoride ion concentration in urine, and that equilibration of the electrode response is not a prerequisite for the measurement of fluoride ion. Recovery experiments are in the range 83 to 90%; in-batch precision is between 0·9 and 1·6% and carryover 2·5% or less.

Determination of p-Toluenesulfonamide in Ice Cream by Combination of Continuous Flow and Liquid Chromatography: Summary of Collaborative Study

1994 ◽  
Vol 77 (3) ◽  
pp. 672-674 ◽  
Author(s):  
Paul R Beuaars ◽  
Remmelt Van Dijk ◽  
Arie Brands
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Continuous Flow ◽  
Collaborative Study ◽  
Ice Cream ◽  
Relative Standard ◽  
On Line ◽  
Positive Results

Abstract A collaborative study of the determination of p-tolu-enesulfonamide (p-TSA) in ice cream by a combination of continuous flow and on-line liquid chromatography was conducted. Seven ice cream samples containing 0-6.35 mg p-TSA/kg at 4 levels (1 blank and 3 pairs of split level samples) were analyzed by 11 laboratories. For all samples analyzed, the repeatability relative standard deviation varied from 2.08 to 3.67%, whereas the reproducibility relative standard deviation ranged from 7.79 to 11.68%. The average p-TSA values for the split levels 1,2, and 3 were 0.55,1.02, and 4.44 mg p-TSA/kg, respectively, with mean recoveries ranging from 76 to 79% (overall recovery range for all levels, 63-101 %). No false positive results were reported for the blank sample, and no interference was encountered by the presence of vanillin in samples. The method has been adopted first action by AOAC INTERNATIONAL.

Determination of Nitrate in Vegetables by Continuous Flow: Interlaboratory Study

1994 ◽  
Vol 77 (6) ◽  
pp. 1522-1529 ◽  
Author(s):  
Paul R Beljaars ◽  
Remmelt Van Duk ◽  
Geertrutoa M Van Der Horst
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Continuous Flow ◽  
Collaborative Study ◽  
Leafy Vegetables ◽  
Collaborative Studies ◽  
Relative Standard ◽  
Metallic Cadmium ◽  
Inspection Service

Abstract A collaborative study for the determination of nitrate in leafy vegetables, such as endive, lettuce, spinach, and beetroot, by continuous flow (CF) was conducted by the Project Group on Collaborative Studies of the Inspectorate for Health Protection, Food Inspection Service, in The Netherlands. After extraction with water and filtration, samples were cleaned up by dialysis in the CF system. Extracted nitrates were reduced to nitrite in the system by metallic cadmium, and then the nitrite was reacted with sulfanilamide and N-naphthylethylenediamine to form a reddish-purple azo dye. This dye was measured colorimetrically at 530 nm. Fourteen vegetable samples (including 7 blind duplicates) containing nitrate at ca 900 to 5200 mg/kg were analyzed singly by the proposed procedure by 13 laboratories. The data were analyzed by the International Union for Pure and Applied Chemistry (IUPAC)–International Organization for Standardization (ISO)–AOAC protocol for statistics. One collaborator was identified as an outlier for all results. For all samples analyzed, the repeatability relative standard deviation values varied from 1.7 to 5.5%, whereas the reproducibility relative standard deviation values ranged from 3.3 to 5.9%.

SIMS Determination of MG+ and AS+ Range Profiles in Photoresist and Polyimide Implant Masks.

1989 ◽  
Vol 147 ◽  
Author(s):  
D. L. Dugger ◽  
M. B. Stern ◽  
T. M. Rubico
Keyword(s):  
Standard Deviation ◽  
Mass Spectroscopy ◽  
Range Data ◽  
Profile Data ◽  
Projected Range ◽  
Range Profile ◽  
P Type ◽  
Secondary Ion ◽  
Good Agreement

AbstractThe distribution of Mg+ (a p-type dopant for GaAs) and As+ (an p-type dopant for Si) implanted into both photoresist (PR) and polyimide (PI) have been determined experimentally. Range data of Mg ions at 200 keV and 300 keV and As ions at 150 keV have been measured by Secondary Ion Mass Spectroscopy (SIMS). SIMS values for the projected range Rp and the standard deviation ARp were compared to range profile data calculated using the Projected Range Algorithm (PRAL) of Biersack [1] as well as the standard LSS theory [2]. While the values for Rp calculated from the PRAL model generally agreed within 10% of the SIMS values, the calculations underestimated Rp for PR but were in good agreement for PI. The LSS calculations underestimated Rp in both materials.

A Semi-Automated Method for the Determination of Ammonia in Urine using the Nessler Reaction

1974 ◽  
Vol 11 (1-6) ◽  
pp. 137-140 ◽  
Author(s):  
T. F. Hartley
Keyword(s):  
Ammonium Chloride ◽  
Continuous Flow ◽  
Flow Analysis ◽  
Zinc Hydroxide ◽  
Automated Method ◽  
Continuous Flow Analysis ◽  
Analar Grade ◽  
Analysis System

Species in urine which were likely to interfere with the determination of ammonia by Nesslerisation were adsorbed onto a precipitate of zinc hydroxide formed in situ in each sample. The ammonia concentrations in the subsequent supernatant solutions were measured using the Nessler method, adapted for use on a continuous flow analysis system. These measurements were made against a series of standards prepared from Analar grade ammonium chloride. The accuracy, reproducibility, and sensitivity of this adaptation were examined and were found to be within acceptable limits.

Collaborative Study of an Automated Method for the Determination of Crude Protein in Animal Feeds

1976 ◽  
Vol 59 (1) ◽  
pp. 141-147
Author(s):  
Rodney J Noel
Keyword(s):  
Crude Protein ◽  
Primary Standard ◽  
Collaborative Study ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
Animal Feeds ◽  
Automated Method ◽  
Kjeldahl Method ◽  
Good Agreement

Abstract An automated macro Kjeldahl instrument determines per cent protein at the rate of 20 samples/hr. The methodology involved is similar to the present official final action Kjeldahl method, sec. 7.016. The 2 methods were compared in a collaborative study. Sixteen animal feeds, 4 meats, tryptophan, ammonium dihydrogen phosphate NBS standard, and ammonium sulfate primary standard were analyzed by the participating laboratories. The data were treated statistically and the results showed good agreement between the 2 methods. The automated method has been adopted as official first action for the determination of crude protein in feeds, plants, and cereal foods.

Automated Chemical Determination of Methionine

1974 ◽  
Vol 57 (3) ◽  
pp. 682-688
Author(s):  
Charles W Gehrke ◽  
Terry E Neuner
Keyword(s):  
Amino Acid ◽  
Standard Deviation ◽  
Ion Exchange ◽  
Automated System ◽  
Automated Method ◽  
Relative Standard ◽  
Chemical Determination ◽  
Sample Recovery ◽  
Hydrolysis Of

Abstract A rapid, accurate, and precise spectrophotometry method, based on the nitroprussidemethionine color reaction, has been developed for the determination of methionine in soybeans, mungbeans, and corn. Amino acid interference was eliminated by partial enzymatic hydrolysis of samples for 4 hr at 50 °C with papain; the samples were analyzed by an automated system. Precision and accuracy were determined by repeated independent analyses of 13 samples of corn, mungbeans, and soybeans; the data were compared to independent classical ion exchange amino acid results. The range for each set of samples varied from 0.02 to 0.04 w/w% methionine. The per cent recovery for 12 of the 13 samples compared to those from ion exchange ranged from 95.2 to 107.1% with an average of 100.2%. The standard deviation varied from 0.01 to 0.02, and the per cent relative standard deviation from 11.8% for a 0.16 w/w% sample to 2.5% for a 0.42 w/w% sample. Recovery of added methionine from corn samples ranged from 92.7 to 102.0% (96.8% average) ; from soybeans 95.0 to 112.0% (101.9% average); and from mungbeans 91.3 to 102.0% (95.8% average). A reliable automated method has been developed which is applicable to different types of biological substances; 20 samples/hr can be analyzed.

Automated Method for the Determination of Deuterium Oxide in Water and Biologic Fluids

1969 ◽  
Vol 15 (1) ◽  
pp. 56-60 ◽  
Author(s):  
R C Robbins
Keyword(s):  
Standard Deviation ◽  
Deuterium Oxide ◽  
Automated System ◽  
Automated Method ◽  
Infrared Spectrophotometer

Abstract An automated system has been assembled for determination of deuterium oxide in water and physiologic fluids. The system consists of an AutoAnalyzer sampler, proportioning pump, and dialyzer; a Perkin-Elmer infrared spectrophotometer; and a Sargent recorder. Reproducibility of peak heights showed a standard deviation of less than ± 1 mm. over a range of D2O concentrations from 0.125 to 1.000%.

Determination of Uric Acid An Automated Phosphotungstate Method Using NaOH as the Alkali

1968 ◽  
Vol 14 (7) ◽  
pp. 630-636 ◽  
Author(s):  
James L Wheat
Keyword(s):  
Quality Control ◽  
Uric Acid ◽  
Standard Deviation ◽  
Sodium Hydroxide ◽  
Serum Uric Acid ◽  
Good Sensitivity ◽  
Automated Method

Abstract An automated method is described for the determination of serum uric acid using sodium hydroxide alone as the alkalinizing agent in the uric acid-phosphotungstate reaction. Turbidity is not a problem and antiturbidity reagents are not needed. At the rate of 40 samples per hour, there is good sensitivity and good correlation with a manual urea-cyanide method. Quality control shows a standard deviation of ± 0.1 mg./100 ml.

Sign in / Sign up

Export Citation Format

Share Document