Radioisotope Dilution Technique for Determination of Vitamin B12 in Foods

1982 ◽  
Vol 65 (1) ◽  
pp. 85-88 ◽  
Author(s):  
Patrick J Casey ◽  
Keevin R Speckman ◽  
Frank J Ebert ◽  
William E Hobbs
Keyword(s):  
Standard Deviation ◽  
Vitamin B12 ◽  
Relative Standard Deviation ◽  
Extraction Procedure ◽  
Dilution Technique ◽  
Microbiological Method ◽  
Relative Standard ◽  
Wide Range ◽  
The Mean

Abstract A radioisotope dilution (RID) method for the determination of vitamin B12 is presented. The method combines a standard extraction procedure (AOAC 43.108,12th ed.) with a commercially available RID assay kit. The method was evaluated on a wide range of fortified and unfortified food products. Recovery studies on both groups yielded average recoveries of 98.1 and 95.8%, respectively. Reproducibility data generated from replicate analyses on both groups gave a relative standard deviation of 6.9% for the fortified group and 9.2% for the unfortified group. For the samples studied, the mean vitamin B12 content determined by the RID method was 8.01 μg/100 g vs imean of 7.54 μg/100 g by the AOAC microbiological method; the correlation coefficient was r = 0.983.

scholarly journals Development and Validation of an ICP-MS Method for Simultaneous Determination of Selected Metals in Electronic Cigarette Aerosol

2018 ◽  
Vol 28 (1) ◽  
pp. 2-13
Author(s):  
Shintaro Ohashi
Keyword(s):  
Standard Deviation ◽  
Nitric Acid ◽  
Simultaneous Determination ◽  
Propylene Glycol ◽  
Relative Standard Deviation ◽  
Icp Ms ◽  
Relative Standard ◽  
The Mean ◽  
The Impact

SummarySafety and quality standards for electronic cigarettes (e-cigarettes) have been introduced regionally. In 2016, the U.S. Food and Drug Administration (FDA) issued a rule to regulate e-cigarettes, requiring to report harmful and potentially harmful constituents (HPHCs). In the United Kingdom, the British Standards Institution (BSI) specified the metals to be monitored for e-cigarettes. In this study, a method was developed and validated for the simultaneous determination of 13 metals (Be, Al, Cr, Fe, Co, Ni, Cu, As, Se, Ag, Cd, Sn and Pb) in e-cigarette aerosol. Furthermore, matrix effects of major constituents in the aerosol were investigated using glycerol or 1,2-propylene glycol solutions. E-cigarette aerosol was generated by a rotary smoking machine according to CORESTA Recommended Method N° 81 and collected by an electrostatic precipitator coupled to an impinger containing nitric acid. The collected aerosol was dissolved in nitric acid and an aliquot of this solution was analyzed by inductively coupled plasma mass spectrometry (ICP-MS) equipped with a collision/reaction cell.The linearity of the calibration curve was observed in the range of 0.2 to 100 ng/mL for each analyte; the correlation coefficients were 0.998 or larger, the mean recovery of each standard level ranged from 92.6 to 104.5% and the relative standard deviation amounted to max. 9.5%. Accuracy, repeatability and specificity were validated by spiking three different amounts of analytes into e-cigarette aerosol; the mean recovery of each spiking level ranged from 88.7 to 110.3% with a relative standard deviation amounting to max. 9.2% for all analytes. Background contamination from aerosol generation and collection system existed for some analytes, especially for Al, Fe, Cu and Sn. The potential sources of contamination should be identified and controlled to reduce the impact of contamination on quantification. In addition, the actual values for samples should be reported with method blank statistics. Increase of the concentrations of glycerol and 1,2-propylene glycol in the prepared sample led to the overestimation of As and Se. The amount of polyols in the collected aerosol should be monitored and controlled for the accurate quantification of As and Se.

scholarly journals Determination of Glyphosate and Aminomethylphosphonic Acid in Crops by Capillary Gas Chromatography with Mass-Selective Detection: Collaborative Study

2001 ◽  
Vol 84 (3) ◽  
pp. 823-846 ◽  
Author(s):  
Philip L Alferness ◽  
Lawrence A Wiebe ◽  
L Anderson ◽  
O Bennett ◽  
M Bosch ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Capillary Gas Chromatography ◽  
Collaborative Study ◽  
Selective Detection ◽  
Aminomethylphosphonic Acid ◽  
Relative Standard ◽  
The Mean

Abstract A collaborative study was conducted to validate a method for the determination of glyphosate and aminomethylphosphonic acid (AMPA) in crops. The analytes are extracted from crops with water, and the crude extracts are then subjected to a cation exchange cleanup. The analytes are derivatized by the direct addition of the aqueous extract into a mixture of heptafluorobutanol and trifluoroacetic anhydride. The derivatized analytes are quantitated by capillary gas chromatography with mass-selective detection (MSD). The collaborative study involved 13 laboratories located in 5 countries 12 laboratories returned valid data sets. The crops tested were field corn grain, soya forage, and walnut nutmeat at concentrations of 0.050, 0.40, and 2.0 mg/kg. The study used a split-level pair replication scheme with blindly coded laboratory samples. Twelve materials were analyzed, including 1 control and 3 split-level pairs for each matrix, 1 pair at each nominal concentration. For glyphosate, the mean recovery was 91%, the average intralaboratory variance, the repeatability relative standard deviation (RSDr), was 11%, and the interlaboratory variance, the reproducibility relative standard deviation (RSDR), was 16%. For AMPA, the mean recovery was 87%, the RSDr was 16%, and the RSDR was 25% at mg/kg levels.

An Automated Procedure for the Determination of Ammonia in Tobacco

1972 ◽  
Vol 6 (4) ◽  
Author(s):  
P.F. Collins ◽  
W.W. Lawrence ◽  
J.F. Williams
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Distillation Method ◽  
Relative Standard ◽  
Tobacco Sample ◽  
Automated Determination

AbstractA procedure for the automated determination of ammonia in tobacco has been developed. Ammonia is extracted from the ground tobacco sample with water and is determined with a Technicon Auto Analyser system which employs separation of the ammonia through volatilization followed by colourimetry using the phenate-hypochlorite reaction. The procedure has been applied to a variety of tobaccos containing from 0.02 to 0.5 % ammonia with an overall relative standard deviation of 2 %. The accuracy of the procedure as judged by recovery tests and by comparison to a manual distillation method is considered adequate

scholarly journals Indirect and Direct Determination of the Casein Content of Milk by Kjeldahl Nitrogen Analysis: Collaborative Study

1998 ◽  
Vol 81 (4) ◽  
pp. 763-774 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming
Keyword(s):  
Standard Deviation ◽  
Nitrogen Content ◽  
Relative Standard Deviation ◽  
Collaborative Study ◽  
Direct Determination ◽  
Raw Milk ◽  
Method Performance ◽  
Relative Standard ◽  
Milk Casein

Abstract The classic method for determination of milk casein is based on precipitation of casein at pH 4.6. Precipitated milk casein is removed by filtration and the nitrogen content of either the precipitate (direct casein method) or filtrate (noncasein nitrogen; NCN) is determined by Kjeldahl analysis. For the indirect casein method, milk total nitrogen (TN; Method 991.20) is also determined and casein is calculated as TN minus NCN. Ten laboratories tested 9 pairs of blind duplicate raw milk materials with a casein range of 2.42- 3.05℅ by both the direct and indirect casein methods. Statistical performance expressed in protein equivalents (nitrogen ⨯ 6.38) with invalid and outlier data removed was as follows: NCN method (wt%), mean = 0.762, sr = 0.010, SR = 0.016, repeatability relative standard deviation (RSDr) = 1.287℅, reproducibility relative standard deviation (RSDR) = 2.146%; indirect casein method (wt℅), mean = 2.585, repeatability = 0.015, reproducibility = 0.022, RSDr = 0.560℅, RSDR = 0.841; direct casein method (wt℅), mean = 2.575, sr = 0.015, sR = 0.025, RSDr = 0.597℅, RSDR = 0.988℅. Method performance was acceptable and comparable to similar Kjeldahl methods for determining nitrogen content of milk (Methods 991.20, 991.21,991.22, 991.23). The direct casein, indirect casein, and noncasein nitrogen methods have been adopted by AOAC INTERNATIONAL.

Determination of Nitrate in Water by HPLC

2013 ◽  
Vol 448-453 ◽  
pp. 406-408
Author(s):  
Jing Liu ◽  
Xiao Na Ji ◽  
Qing Kai Ren ◽  
Sheng Shu Ai ◽  
Li Jun Wan ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Recovery Rate ◽  
High Performance ◽  
Separation Efficiency ◽  
Fast Analysis ◽  
Relative Standard

We established a method fordetermination of nitrate in water by High Performance Liquid Chromatography(HPLC). The sample was analysed by HPLC-ADA and was quantitated by externalstandard method after being simply processed. This methd has the advantages ofhigh separation efficiency and fast analysis. The experiment result showed thatthe linearly dependent coefficient was0.994, the recovery rate was between 98.7%～105.7%,the relative standard deviation（RSD）wasless than 2.1 %, and the lowest detectable limit is 0.01ng (S/N=1.6).

scholarly journals Determination of 1,3-Dichloropropanol in Soy Sauce and Related Products by Headspace Gas Chromatography with Mass Spectrometric Detection: Interlaboratory Study

2005 ◽  
Vol 88 (5) ◽  
pp. 1404-1412 ◽  
Author(s):  
Sarah Hasnip ◽  
Colin Crews ◽  
Nicholas Potter ◽  
Paul Brereton ◽  
Henri Diserens ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Internal Standard ◽  
Mass Spectrometric ◽  
Soy Sauce ◽  
Headspace Gas Chromatography ◽  
Relative Standard ◽  
Headspace Gas

Abstract An interlaboratory study was performed to evaluate the effectiveness of a headspace gas chromatography (GC) method for the determination of 1,3-dichloro-propan-2-ol (1,3-DCP) in soy sauce and related products at levels above 5 ng/g. The test portion is mixed with an internal standard (d5-1,3-DCP) and ammonium sulfate in a sealed headspace vial. After achieving equilibrium, the headspace is sampled either by gas-tight syringe or solid-phase microextraction (SPME) and analyzed by GC with mass spectrometric detection. 1,3-DCP is detected in the selected-ion mode (monitoring m/z 79 and 81 for 1,3-DCP and m/z 82 for the deuterated internal standard) and quantified by measurement against standards. Test materials comprising soy, dark soy, mushroom soy, and teriyaki sauces, both spiked and naturally contaminated, were sent to 9 laboratories in Europe, Japan, and the United States; of these, 5 used SPME and 4 used syringe headspace analysis. Test portions were spiked at 5.0, 10.0, 20.0, 100.0, and 500.0 ng/g. The average recovery for spiked blank samples was 108% (ranging from 96–130%). Based on results for spiked samples (blind pairs at 5, 10, 20, 100, and 500 ng/g) as well as a naturally contaminated sample (split-level pair at 27 and 29 ng/g), the relative standard deviation for repeatability (RSDr) ranged from 2.9–23.2%. The relative standard deviation for reproducibility (RSDR) ranged from 20.9–35.3%, and HorRat values of between 1.0 and 1.6 were obtained.

scholarly journals Development and validation of spectrophotometric method for phenylephrine hydrochloride estimation in nasal drops formulations

2008 ◽  
Vol 27 (2) ◽  
pp. 149 ◽  
Author(s):  
Ivana Savić ◽  
Goran Nikolić ◽  
Vladimir Banković
Keyword(s):  
Standard Deviation ◽  
Sodium Hydroxide ◽  
Relative Standard Deviation ◽  
Spectrophotometric Method ◽  
Molar Absorptivity ◽  
Dosage Forms ◽  
Phenylephrine Hydrochloride ◽  
Relative Standard ◽  
Development And Validation

Simple, accurate and reproducible UV-spectrophotometric method was developed and validated for the estimation of phenylephrine hydrochloride in pharmaceutical nasal drops formulations. Phenylephrine hydrochloride was estimated at 291 nm in 1 mol⋅dm-3 sodium hydroxide (pH 13.5). Beer’s law was obeyed in the concentration range of 10–100 μg⋅cm−3 (r2 = 0.9990) in the sodium hydroxide medium. The apparent molar absorptivity was found to be 1.63×103 dm3⋅mol−1⋅cm−1. The method was tested and validated for various parameters according to the ICH (International Conference on Harmonization) guidelines. The detection and quantitation limits were found to be 0.892 and 2.969 μg⋅cm−3, respectively. The proposed method was successfully applied for the determination of phenylephrine hydrochloride in pharmaceutical nasal drops formulations. The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation < 1 %), while being simple, cheap and less time consuming, and hence can be suitably applied for the estimation of phenylephrine hydrochloride in different dosage forms.

scholarly journals Badanie stabilności barwnych znaczników fluorescencyjnych w silnie zasiarczonych wodach złożowych

Nafta-Gaz ◽  
2021 ◽  
Vol 77 (2) ◽  
pp. 82-91
Author(s):  
Katarzyna Wojtowicz ◽  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Rhodamine B ◽  
Water Reservoir ◽  
Distilled Water ◽  
Test Results ◽  
Fluorescent Tracers ◽  
Reservoir Water ◽  
Relative Standard

The article presents the issues related to the determination of colored fluorescent tracers such as fluorescein, eosin yellowish, rhodamine B and uranine in reservoir waters by spectrophotometric method. For this purpose, the influence of the pH of the solution on the absorption spectra of the tested tracers was checked. Test results show that fluorescein, rhodamine B and uranine are sensitive to changes in the buffer pH, therefore it is advisable to use stable tracer solutions as well as to control and possibly correct pH in further tests. As part of the study, calibration curves of fluorescein, eosin yellowish, rhodamine B and uranine in distilled water, reservoir water A4 and highly sulfated reservoir waters A5 and A6 were plotted and the analytical methods were validated. Analytical validation included determination of linearity, standard deviation and relative standard deviation of the tested tracers solutions. High values of the regression parameters (0.9927–0.9998) of the analyzed tracers prove a good linear fit, while low values of standard deviation and relative standard deviation prove its repeatability and precision. Particular attention was paid to testing the stability of colored fluorescent tracers in highly sulfated reservoir waters. For this purpose, solutions of the tested tracers were prepared at concentrations of 10 mg/dm3 in distilled water, A4 reservoir water and highly sulfated A5 and A6 reservoir waters. Measurements of the tested tracers in the prepared solutions were performed every 2 days over the period of 1 month. The test results show that fluorescein, eosin yellowish, rhodamine B and uranine solutions are stable in the distilled water and A4 reservoir water, while they degrade in the A5 and A6 reservoir waters. Fluorescein and uranine turned out to be the most sensitive, as they degraded completely in the A6 reservoir water after 20 (fluorescein) and 22 (uranine) days. Yellowish eosin and rhodamine B turned out to be slightly more stable in highly sulfated reservoir waters, as they degraded completely in the A6 reservoir water after 24 days.

scholarly journals Interlaboratory Evaluation of Two Enzyme-Linked Immunosorbent Assay Kits for the Determination of Crustacean Protein in Processed Foods

2008 ◽  
Vol 91 (1) ◽  
pp. 123-129 ◽  
Author(s):  
Shinobu Sakai ◽  
Rieko Matsuda ◽  
Reiko Adachi ◽  
Hiroshi Akiyama ◽  
Tamio Maitani ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Immunosorbent Assay ◽  
Soluble Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Processed Foods ◽  
Relative Standard ◽  
High Level

Abstract The labeling of foods containing material derived from crustaceans such as shrimp and crab is to become mandatory in Japan because of increases in the number of allergy patients. To ensure proper labeling, 2 novel sandwich enzyme-linked immunosorbent assay (ELISA) kits for the determination of crustacean protein in processed foods, the N kit (Nissui Pharmaceutical Co., Ltd, Ibaraki, Japan) and the M kit (Maruha Nichiro Holdings, Inc., Ibaraki, Japan), have been developed. Five types of model processed foods containing 10 and/or 11.9 g/g crustacean soluble protein were prepared for interlaboratory evaluation of the performance of these kits. The N kit displayed a relatively high level of reproducibility relative standard deviation (interlaboratory precision; 4.08.4 RSDR) and sufficient recovery (6586) for all the model processed foods. The M kit displayed sufficient reproducibility (17.620.5 RSDR) and a reasonably high level of recovery (82103). The repeatability relative standard deviation (RSDr) values regarding the detection of crustacean proteins in the 5 model foods were mostly &lt;5.1 RSDr for the N kit and 9.9 RSDr for the M kit. In conclusion, the results of this interlaboratory evaluation suggest that both these ELISA kits would be very useful for detecting crustacean protein in processed foods.

Determination of Maleic Hydrazide Residues in Tobacco and Vegetables

1973 ◽  
Vol 56 (5) ◽  
pp. 1164-1172
Author(s):  
Milan Ihnat ◽  
Robert J Westerby ◽  
Israel Hoffman
Keyword(s):  
Standard Deviation ◽  
Present Method ◽  
Maleic Hydrazide ◽  
Collaborative Study ◽  
Official Method ◽  
Sample Weight ◽  
Relative Standard ◽  
The Mean ◽  
Pipe Tobacco

Abstract The distillation-spectrophotometric method of Hoffman for determining maleic hydrazide has been modified to include a double distillation and was applied to the determination of 1–30 ppm maleic hydrazide residues in tobacco and vegetables. Recoveries of 1–23 μg added maleic hydrazide were independent of weight of maleic hydrazide, but did depend on sample and sample weight. The following recoveries were obtained from 0.5 g sample: pipe tobacco, 84%; commercially dehydrated potato, 83%; cigar tobacco, 81%; dried potato, 76%; fluecured tobacco, 73%; dried carrot, 71%. In the absence of sample, the recovery was 82%. When appropriate standard curves were used, maleic hydrazide levels determined in tobacco samples were essentially independent of sample weight in the range 0.1–3 g. The mean relative standard deviation for a variety of field-treated and fortified tobacco samples containing 1–28 ppm maleic hydrazide was 3%. The precision and sensitivity of this procedure seem to be substantial improvements over official method 29.111–29.117. It is recommended that the present method be subjected to a collaborative study.

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