Collaborative Study of the Spectrophotometric Determination of Phosphatase Activity in Milk Utilizing a New Alkaline Phosphatase Assay System

1972 ◽  
Vol 55 (3) ◽  
pp. 498-503
Author(s):  
D H Kleyn ◽  
C L Huang
Keyword(s):  
Systematic Error ◽  
Collaborative Study ◽  
Correlation Coefficients ◽  
New Method ◽  
Statistical Comparison ◽  
Alkaline Phosphatase Assay ◽  
Phosphatase Assay ◽  
Method Analysis ◽  
Quantitative Procedure

Abstract A quantitative procedure (modified new method) has been studied that employs phenolphthalein monophosphate as the substrate and dialysis of released phenolphthalein followed by subseqvient measurement of the dialysate in a spectrophotometer at 550 nm. Nine collaborators evaluated 6 unknown samples of milk containing various levels of rawmilk, in triplicate, by the modified new method and the Scharer modified spectrophotometric method. Analysis of variance revealed that the random error of the modified new method was almost twice that of the Scharer technique, while the systematic error of the modified new method was only about ¼ that of the latter method. Two-sample charts indicated that the systematic error of the modified new method was less than that of the Scharer method; this was verified by a statistical comparison which showed that the total analytical error was much lower for the modified new method. A linear relationship was found between the 2 methods by 5 of the collaborators; the correlation coefficients ranged from 0.993 to 0.999. Based on these results, the method has been adopted as official first action for the analysis of milk.

Collaborative Study of a New Alkaline Phosphatase Assay System for Milk

1968 ◽  
Vol 51 (4) ◽  
pp. 802-807 ◽  
Author(s):  
D H Kleyn ◽  
S H C Lin
Keyword(s):  
Alkaline Phosphatase ◽  
Statistical Study ◽  
Collaborative Study ◽  
Skim Milk ◽  
New Method ◽  
Chi Square ◽  
Alkaline Phosphatase Assay ◽  
Whole Milk ◽  
Phosphatase Assay ◽  
Tests Of Independence

Abstract A new method in which phenolphthalein monophosphate is used as substrate has been developed for determining residual alkaline phosphatase: Upon hydrolysis, phenolphthalein is released and yields a red solution that is compared visually with a standard prepared from the same milk. Seven collaborators made 168 observations that were used in a statistical study of the results. Chi-square calculations and tests of independence indicated that the described method yields results on skim milk, whole milk, and light cream that are as precise and either as accurate or more accurate than those obtained with the Scharer I method. Based on these results, it is recommended that the method be adopted as official, first action.

scholarly journals Extractive Spectrophotometric Methods for Determination of Zolmitriptan in Tablets

2007 ◽  
Vol 90 (5) ◽  
pp. 1237-1241 ◽  
Author(s):  
Zeynep Aydogmus ◽  
Ipek Inanli
Keyword(s):  
High Performance ◽  
Correlation Coefficients ◽  
Bromothymol Blue ◽  
Chromatography Method ◽  
Statistical Comparison ◽  
Spectrophotometric Methods ◽  
Accuracy And Precision ◽  
Liquid Chromatography Method ◽  
Comparison Of The Results

Abstract Two simple and sensitive extractive spectrophotometric methods have been developed for determination of zolmitriptan (ZTP) in tablets. These methods are based on the formation of yellow ion-pair complexes between ZTP and tropaeolin OO (TPOO) and bromothymol blue (BTB) in citratephosphate buffer of pH 4.0 and 6.0, respectively. The formed complexes were extracted with dichloromethane and measured at 411.5 and 410 nm for TPOO and BTB, respectively. The best conditions of the reactions were studied and optimized. Beer's law was obeyed in the concentration ranges of 220 and 1.517 g/mL with molar absorptivities of 1.42 104 and 1.60 104 L/mol/cm for the TPOO and BTB methods, respectively. Correlation coefficients were 0.9998 and 0.9999 for TPOO and BTB methods, respectively. Limits of detection of the TPOO and BTB methods were 0.341 and 0.344 g/mL, respectively, and the limits of quantitation were 1.034 and 1.051 g/mL, respectively. Sandell's sensitivity and stability constant were also calculated. The proposed methods have been applied successfully for the analysis of the drug in its dosage forms. No interference was observed from excipients present in tablets. Statistical comparison of the results with those obtained by a high-performance liquid chromatography method showed excellent agreement and indicated no significant differences in accuracy and precision.

An Automated Alkaline Phosphatase Assay with Phenolphthalein Monophosphate as Substrate

1967 ◽  
Vol 13 (4) ◽  
pp. 281-289 ◽  
Author(s):  
Kirsten Hviid
Keyword(s):  
Alkaline Phosphatase ◽  
Normal Values ◽  
Serum Alkaline Phosphatase ◽  
Colorimetric Determination ◽  
Alkaline Phosphatase Assay ◽  
Phosphatase Assay ◽  
Hydrolysis Of

Abstract The manual procedure of Babson et al. (1) for the determination of serum alkaline phosphatase has been automated. The assay is based on the colorimetric determination of phenolphthalein formed on hydrolysis of phenolphthalein monophosphate. The procedure utilizes 0.16 ml. of serum without dialysis. Blanks are required only for turbid sera. Results are compared with those obtained by the manual procedure, and data relating to sample interaction, precision, blank values, and normal values are presented.

Determination of Phosphorus in Processed Cheese: Collaborative Study

1985 ◽  
Vol 68 (1) ◽  
pp. 102-104
Author(s):  
Gerald Steiger ◽  
William Horwitz ◽  
Lambrecht J Poortvliet ◽  
Petter Soderhjelm
Keyword(s):  
Systematic Error ◽  
Collaborative Study ◽  
Accuracy Control ◽  
Processed Cheese ◽  
Molybdenum Blue ◽  
Final Measurement ◽  
Cheese Products

Abstract A second interlaboratory collaborative study of the determination of phosphorus in processed cheese products by the molybdenum blue method verifies that this method is prone to producing a laboratoryinduced systematic error. It would be useless to continue to make minor modifications in the details of the method, which will improve only the within-laboratory precision, until an accuracy control of the final measurement step is incorporated into the method.

Collaborative Study of the Thermistor Cryoscopic Method for the Determination of the Freezing Point Value of Milk

1968 ◽  
Vol 51 (4) ◽  
pp. 816-821
Author(s):  
R W Henningson
Keyword(s):  
Standard Deviation ◽  
Systematic Error ◽  
Freezing Point ◽  
Collaborative Study

Abstract Data from 19 collaborators for two sample pairs were used to estimate the precision and systematic error of the thermistor cryoscopic method for determining the freezing point value of milk. Precision was greater for the milks (0.0015°) than for the standards (0.004°). The systematic error was estimated to be 0.0033°. The standard deviation for interlaboratory individual determinations was estimated to be 0.0049°.

UTILIZATION OF PHENOLPHTHALEIN MONOPHOSPHATE TO TO DETERMINE THE PHOSPHATASE ACTIVITY OF MILK1

1972 ◽  
Vol 35 (7) ◽  
pp. 405-409 ◽  
Author(s):  
Dick H. Kleyn
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Rapid Method ◽  
Alkaline Phosphatase Activity ◽  
Collaborative Study ◽  
Correlation Coefficients ◽  
Raw Milk ◽  
New Method ◽  
Chocolate Milk ◽  
Positive Correlations

The properties of alkaline phosphatase as it exists in milk are considered. The more common methods of measuring alkaline phosphatase activity in milk are briefly reviewed, especially those employing substrates possessing “built-in” indicators which produce a chromogen directly upon hydrolysis. The visual procedure employing phenolphthalein monophosphate as the substrate is given. The sensitivity of this method is shown to be far greater than that of the Scharer I (Rapid) method. Results of an AOAC Collaborative study demonstrated that the method yields results that are as precise and either as accurate as or more accurate than those obtained by the Scharer I (Rapid) method. The quantitative spectrophotometric procedure employing the above substrate is presented. Comparison of this method with the Scharer modified spectrophotometric method on milk revealed correlation coefficients (Scharer method: 0.998 and modified new method 0.991) showing very little difference in the positive correlations of absorbance values and % raw milk. For chocolate milk, the values were 0.990 and 0.990 for the respective methods. Collaborative study of this method has demonstrated that the random error of the modified new method is almost twice that of the Scharer technique while the systematic error is only about one-fourth of the latter method.

Collaborative Study of a Colorimetric Determination of Nitrate in Tobacco

1969 ◽  
Vol 52 (4) ◽  
pp. 756-759
Author(s):  
C James Rosene
Keyword(s):  
Sulfuric Acid ◽  
Standard Deviation ◽  
Systematic Error ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Water Soluble ◽  
Colorimetric Determination ◽  
Error Standard Deviation

Abstract A colorimetric method for determining water-soluble nitrate in tobacco was studied by 14 laboratories on eight Burley and two cigar filler tobacco samples with nitrate levels of 0.5–2.4%. In the method, ground tobacco is extracted with water and filtered, and an aliquot is then treated with 2,4-xylenol in sulfuric acid; then the resulting 6-nitro-2,4-xylenol is removed by distillation and measured spectrophotometrically at 450 µm. Results show that, althoughthe precision standard deviation among laboratories is generally acceptable, the systematic error standard deviation is unacceptably high. This study will be continued.

scholarly journals Spectrophotometric Method for Determination of Five 1,4-Dihydropyridine Drugs Using N-Bromosuccinimide and Indigo Carmine Dye

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Mohamed A. El Hamd ◽  
Sayed M. Derayea ◽  
Osama H. Abdelmageed ◽  
Hassan F. Askal
Keyword(s):  
Spectrophotometric Method ◽  
Indigo Carmine ◽  
Correlation Coefficients ◽  
Dosage Forms ◽  
Variance Ratio ◽  
Statistical Comparison ◽  
Significant Difference ◽  
Beer’S Law ◽  
Indigo Carmine Dye

Indirect spectrophotometric method is described for quantification of five of 1,4-dihydropyridine (1,4-DHP) drugs using N-bromosuccinimide (NBS) with the aid of indigo carmine (INC) dye. The method is based on addition of known excess of NBS to an acidified solution of 1,4-DHP drugs and determining the residual of NBS through its ability to bleach the colour of the used dye; the amount of NBS that reacted corresponded to the amount of drugs. Beer’s law is obeyed in the concentration range 1.25–13.00 μg/mL. Good correlation coefficients (0.998-0.999) were found between the absorbance values and the corresponding concentrations. Limits of detections ranged from 0.141 to 0.500 μg/mL. The proposed method was successfully applied to the analysis of dosage forms; percent of recoveries ranged from 97.31 to 99.46% without interference from any common excipients. The statistical comparison by Student’s t-test and variance ratio F-test showed no significant difference between the proposed and official or reported methods.

Collaborative Study of the Official AOAC Flame Photometric Method for the Determination of Sodium in Fertilizers

1972 ◽  
Vol 55 (5) ◽  
pp. 986-988
Author(s):  
Luis F Corominas
Keyword(s):  
Ion Exchange ◽  
Systematic Error ◽  
Collaborative Study ◽  
Flame Photometry ◽  
Photometric Method ◽  
Standard Deviations

Abstract The present official final action method, 2.132–2.135 (11 th Ed.), has been compared with the 10th Edition method, 2.117–2.120; the need for ion exchange cleanup before flame photometry was also studied for samples containing 0.1-0.7% sodium. In general, the 11th Edition method produced more precise results; elimination of ion exchange treatment improved values obtained for the standard deviations of the systematic error. These findings are based on 600 individual results reported by 9 laboratories for 4 samples.

Collaborative Study of a Gas Chromatographic Method for the Analysis of Diazinon

1971 ◽  
Vol 54 (3) ◽  
pp. 700-702
Author(s):  
R T Murphy ◽  
A H Hofberg ◽  
H R Buser
Keyword(s):  
Systematic Error ◽  
Coefficient Of Variation ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Internal Standard ◽  
Peak Height ◽  
Matched Pair ◽  
Flame Ionization ◽  
Gas Chromatographic Method

Abstract A gas chromatographic method for the determination of Diazinon in liquid formulations containing about 50% active ingredient was collaboratively studied, using a matched pair scheme. The sample was dissolved in acetone containing aldrin as an internal standard and chromatographed on silicone DC-200, using a flame ionization detector. Determinations on the 2 samples by 18 collaborators using peak height measurements show an overall coefficient of variation of 1.0%. The coefficient of variation of random error is 0.8%, and for the systematic error, 0.4%. Application of the F-test proved this systematic error not to be significant. The method has been adopted as official first action.

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