bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Total, Soluble, and Insoluble Dietary Fiber in Foods—Enzymatic-Gravimetric Method, MES-TRIS Buffer: Collaborative Study
Authors: Lee Sungsoo C , Prosky Leon , Vries Jonathan W De
Published: February 2020

A joint AOAC/AACC (American Association of Cereal Chemists) collaborative study of methods for the determination of soluble, insoluble, and total dietary fiber (SDF, IDF, and TDF) was conducted with 11 participating laboratories. The assay Is based on a modification of the AOAC TDF method 985.29 and the SDF/IDF method collaboratively studied recently by AOAC. The principles of the method are the same as those for the AOAC dietary fiber methods 985.29 and 991.42, Including the use of the same 3 enzymes (heat-stable α-amylase, protease, and amyloglucosldase) and similar enzyme Incubation conditions. In the modification, minor changes have been made to reduce analysis time and to Improve assay precision: (1) MES-TRIS buffer replaces phosphate buffer; (2) one pH adjustment step Is eliminated; and (3) total volumes of reaction mixture and filtration are reduced. Eleven collaborators were sent 20 analytical samples (4 cereal and grain products, 3 fruits, and 3 vegetables) for duplicate blind analysis. The SDF, IDF, and TDF content of the foods tested ranged from 0.53 to 7.17, 0.59 to 60.53, and 1.12 to 67.56 g/100 g, respectively. The respective average RSDR values for SDF, IDF, and TDF determinations by direct measurements were 13.1, 5.2, and 4.5%. The TDF values calculated by summing SDF and IDF were in excellent agreement with the TDF values measured independently. The modification did not alter the method performance with regard to mean dietary fiber values, yet It generated lower assay variability compared with the unmodified methods. The method for SDF, IDF, and TDF (by summing SDF and IDF) has been adopted first action by AOAC International.
Quantitation of Microorganisms in Raw Minced Meat Using the Direct Epifluorescent Filter Technique: NMKL Collaborative Study
Authors: Boisen Flemming , Skovgaard Niels , Ewald Steen , Olsson Gunnar , Wirtanen Gun
Published: February 2020

Fourteen Nordic laboratories participated In an Interlaboratory study of microorganisms In raw minced meat. After 2 preliminary collaborative evaluations of 20 and 6 prepared direct epifluorescent filter technique (DEFT) slides, the equipment and the counting technique were adjusted and standardized. In the following third and final trial, the laboratories examined 10 samples in duplicate. A special model was developed for homogenlzatlon, preservation, and transport of raw minced meat within 24 h. Test microorganisms were those present naturally In the meat. The participating laboratories received Identical samples in duplicate at 10 counting levels. The results Indicated a coefficient of variation of 15% by Interlaboratory counting of 26 prepared DEFT slides. By examining samples of raw minced meat for microorganisms showing any degree of orange fluorescence, the repeatability and the reproducibility were 0.41 and 0.78, respectively. The repeatability standard deviation (sr) was0.14, and the reproducibility standard deviation (SR) was 0.27. The study demonstrated that DEFT Is a dependable method for quantitation of microorganisms in raw minced meat. Precision of DEFT was in agreement with Nordic Committee on Food Analysis standard deviation values used In the Nordic countries for plate-count quality control.
Evaluation of the Color of Some Spanish Unifloral Honey Types as a Characterization Parameter
Authors: Castro R Mateo , Escamilla M Jiménez , Reig F Bosch
Published: February 2020

The color of 7 types of Spanish unifloral honey from rosemary, orange blossom, lavender, eucalyptus, sunflower, heather, and honeydew was Investigated for Its potential use as a characterization parameter. Colors were estimated by visual comparison with a Lovlbond 1000 Instrument, the readings of which were transformed Into Pfund units. As an alternative method, the transmittances of liquid samples at selected wavelengths were measured, trlstlmulus values were calculated, and chromatic coordinates In the CIE-1931 (x,y,L) and CIE-1976 (L*a*b*) color spaces were determined. The correlation coefficient between x and the Pfund grading was 0.958, but visual comparisons proved to be less objective and precise than CIE parameters; yet, analysis by visual comparison can be used by unskilled dealers and beekeepers because of Its great simplicity. A stepwise discriminant analysis revealed that CIE-1976 (L*a*b*) coordinates yield an overall proportion of accurately classified samples slightly better than that afforded by CIE-1931 coordinates (76 vs 71%). However, rosemary and lavender honeys were more accurately classed by using the CIE-1931 system. The results show that color determinations make a useful tool for helping to classify honeys.
Reversed-Phase Liquid Chromatographic Determination of Vitamin D in Infant Formulas and Enteral Nutritionals
Authors: Sliva Matthew G , Green Astor E , Sanders James K , Euber John R , Saucerman Janice R
Published: February 2020

Vitamin D In infant formulas and enteral nutritional products is determined by reversed-phase liquid chromatography (LC) with UV detection. The sample Is saponified 30 mln at 60°C and extracted Into 60 mL hexane. The hexane layer is then washed and evaporated to dryness. The sample Is reconstituted and added to a 3 mL silica solid-phase extraction column. Vitamins D2 and D3 are eluted from the column with 7 mL methylene chlorlde-lsopropanol mixture (99.8 + 0.2). The eluant is evaporated to dryness and reconstituted In 1 mLacetonltrlle. The acetonitrile solution is analyzed on a C18 reversed-phase LC column (25 cm x 4.6 mm, 5 μm particle size) with UV detection at 265 nm. Linearity for this method between 8 and 2600 lU/qt has shown a coefficient of determination of 1.000, with method precision ranging from 1 to 6%. Spike recoveries gave a mean of 99.1%. Because this method can quantitate and distinguish between vitamin D2 and vitamin D3 In products, vitamin D2 is used as an Internal standard In quantltatlng vitamin D3, and vice versa. The method Is applicable to milk-, soy-, and protein hydrolysate-based infant formulas and enteral nutritional products, both liquid and powder. The sample throughput is estimated to be 24 per day. An AOAC collaborative study of this method is recommended.
Analytical Use of Linear Regression. Part I: Regression Procedures for Calibration and Quantitation
Authors: Mactaggart Douglas L , Farwell Sherry O
Published: February 2020

Although commonly used by analysts, linear regression requires careful attention to 5 fundamental assumptions. This paper summarizes these assumptions and describes the effects of deviations from these assumptions and various approaches to correct for such deviations. Specific cases are defined where classical unweighted or weighted linear regression methods are still applicable in calibration experiments, even though the independent x-variable contains random error. Another topic of this paper is the proper construction of confidence intervals, not only for the relatively easy case of predicting a response value given an analyte concentration (or amount) value but also for the theoretically more difficult case of predicting a concentration (or amount) value given a response value. Various approaches based on single-use discrimination intervals (SDI), multiple-use discrimination intervals (MDI), and unlimited-use discrimination intervals (UDI) are discussed for the latter case. This discussion examines both the theory and analytical applicability of each approach. A simplified procedure based on calculated g-values is introduced for guidance on whether or not to use the SDI approximation. The lengths of the MDIs and UDIs are compared for several test data sets, and the modified Scheffe UDI approach is found to be advantageous because of its relative simplicity and short intervals. Its use is recommended when neither of the described SDI approaches is appropriate, i.e., when the comparison of several predicted analyte concentration (or amount) values obtained from the same calibration curve is desired.
Analytical Use of Linear Regression. Part II: Statistical Error in Both Variables
Authors: Mactaggart Douglas L , Farwell Sherry O
Published: February 2020

This paper critically evaluates the literature techniques that attempt to incorporate the existence of both x- and y- errors into linear regression statistics. This evaluation focuses on the relative theoretical and practical merits of 4 techniques: (1) the effective variance approach, (2) the constant variance ratio approach, (3) the York approach, and (4) the Williamson approach. The practical use of these different approaches is illustrated with the aid of actual results from an interlaboratory comparison study. On the basis of our comparative evaluation, the constant variance ratio approach is sound, yet simple, and is strongly recommended as long as the constant ratio criterion can be satisfied. However, the Williamson approach is applicable in more situations and is also highly recommended because of its theoretical virtues, mathematical consistencies, and practical applications. The other 2 methods are not recommended for use because of reasons that are summarized in this paper. The lack of available software remains an impediment to widespread use of many of the described statistical procedures.
Trace Metals in Edible Tissues of Livestock and Poultry
Authors: Coleman Margaret E , Elder Robert S , Basu Parthaprattim , Koppenaal Gary P
Published: February 2020

Data from a random-sampling study are presented for trace metals in edible tissues of livestock (bovine including bull, steer, cow, heifer, calf; ovine including mature sheep and lambs; porcine including market hogs, boar/stag, and sow) and poultry (including young and mature chicken, young turkey, and duck). Tissue homogenates were ashed, and residual materials were dissolved in hydrochloric acid for analysis by atomic absorption spectroscopy. Statistical summaries of data are provided for the trace metals lead, cadmium, cobalt, copper, iron, manganese, nickel, and zinc. The heavy metals of toxicological concern, lead and cadmium, are emphasized in this study. Lead and cadmium were rarely detected in muscle (0.2-0.5% positive among 2314 animals sampled). Lead was also infrequently detected in liver (1.8% positive) and kidney (2.4% positive). Nearly 46% of livers analyzed were positive for cadmium, and approximately 78% of kidney samples were positive for cadmium. No regulatory limits are established in the United States for the trace metals reported in this study, although restrictions on the use of kidneys from mature poultry as human food have been established because of concern about potential cadmium levels. Kidneys from this study, more frequently than livers, bore cadmium levels that exceeded the regulatory limits of other countries or organizations. Regulatory implications of the data are discussed.
Comparison of Different Methods for Determination of Dietary Fiber
Authors: Wolters Mechteldis G E , Verbeek Cornelis , Van Westerop Johannes J M , Hermus Ruud J J , Voragen Alfons G J
Published: February 2020

Several methods are available for determination of dietary fiber. To increase insight into the relative merits of these methods, the acid-detergent fiber (ADF) and neutral-detergent fiber (NDF) methods of Van Soest et al., the Hellendoorn method, the method of Prosky et al. (AOAC method), and the Englyst method were compared with respect to the amount and the nonstarch polysaccharide (NSP) composition of dietary fiber determined in 4 food products. Our results show that the ADF/NDF detergent methods are inaccurate for the determination of cellulose, hemicellulose, and lignin, and that the NDF and Hellendoorn methods are less-suited for the determination of insoluble dietary fiber. There is a discrepancy between the amount and the NSP composition of the dietary fiber determined by the AOAC and Englyst methods. This is because of either overestimation of the amount of dietary fiber in the AOAC method (coprecipitation of oligosaccharides or Maillard reaction products) or to underestimation of the amount of dietary fiber in the Englyst method (loss of polysaccharides during hydrolysis or derivatization), or both. Differences in isolation methods lead to differences in amounts of soluble and insoluble dietary fiber found by different methods. For both the Englyst and the AOAC methods, calculation of the amount of soluble dietary fiber from the difference between total and insoluble dietary fiber is preferable, because large errors may occur in determining the soluble portion. We have shown that although different methods can yield comparable dietary fiber values, the NSP composition can vary greatly. Therefore, we recommend using those methods that determine specifically well-defined components of the dietary fiber. The chromatographic Englyst method is preferred for this reason, and because it gives insight into the type of polysaccharides present.
Hard Surface Carrier Test for Efficacy Testing of Disinfectants: Collaborative Study
Authors: Rubino Joseph R , Bauer Janice M , Clarke Paul H , Woodward Betsy B , Porter Fran C , Hilton H Gill
Published: February 2020

A collaborative study was undertaken to evaluate a new disinfectant efficacy method called the hard surface carrier test. This new method is a qualitative carrier test that uses disposable glass carriers and standardized bacterial cultures. Ten laboratories tested 6 disinfectant-type formulations, which included positive and negative controls, against 3 microorganisms. No significant differences were found among the 10 laboratories for tests with Pseudomonas aeruginosa and Salmonella choleraesuis, but a small but statistically significant difference was present among laboratories for Staphylococcus aureus. The majority of data for this organism showed very good agreement; however, several tests exhibited slightly higher positive responses, which resulted in this overall difference. This difference was not considered significant within the scope and precision of this method or when compared with results for the other 2 organisms. The initial estimates of pure intralaboratory variance, determined from mean squares from analysis of variance results, were 1.009,0.295, and 1.553 for P. aeruginosa, S. aureus, and S. choleraesuis, respectively. The experimental error for S. aureus was 3-5 times smaller than for the other 2 organisms, which helps explain the statistical significance of the results observed with this organism. Final estimates of intralaboratory variance obtained after dropping nonsignificant terms from the models were 0.90,0.30, and 0.58 for P. aeruginosa, S. aureus, and S. choleraesuis, respectively. Small but statistically significant differences were noted in the formulation means for P. aeruginosa and S. aureus but not for S. choleraesuis. The results of this study suggested a performance standard of ≤2 positive carriers out of 60 tested for S. aureus and S. choleraesuis, and ≤3 positive carriers out of 60 tested for P. aeruginosa. This standard was derived from an analysis of the data by calculating an expected count of positive carriers and a 95% upper confidence limit for a set of 60 carriers. The method has been adopted first action by AOAC International.
Liquid Chromatographic Determination of Ivermectin in Bovine Milk: Interlaboratory Study
Authors: James Kijak Philip
Published: February 2020

A laboratory trial was completed for an analytical method that can quantitate the marker residue of ivermectin, 22,23-dihydroavermectin B1a, in bovine milk at 1 ng/mL Currently, ivermectin is not approved for use in lactating dairy cows. In this method, the ivermectin residues are isolated from the milk matrix by a series of liquid-liquid extractions. A fluorescent derivative of the marker compound is prepared and then quantified by liquid chromatography with fluorescence detection. The interlaboratory study was successfully completed by using dosed milk and milk fortified with marker residue at 1,2, and 4 ng/mL. The average recoveries by the 3 participating laboratories were 87,59, and 95% at 1 ng/mL; 90,61, and 96% at 2 ng/mL; and 90,73, and 99% at 4 ng/mL. The concentrations of the marker residue in the dosed milk were 4.3, 3.7, and 4.7 ng/mL; coefficients of variation were 4.0,24.8, and 5.9%, respectively.
Simultaneous Determination of Sulfonamides in Honey by Liquid Chromatography
Authors: Horie Masakazu , Saito Koichi , Nose Norihide , Nakazawa Hiroyuki
Published: February 2020

A simple and rapid method using liquid chromatography (LC) for the simultaneous determination of 10 sulfonamides (sulfathiazole, sulfadimethoxine, sulfamonomethoxine, sulfadiazine, sulfamerazine, sulfadimidine [sulfamethazine], sulfamethoxazole, sulfamethoxypyridazine, sulfachloropyridazine, and sulfaquinoxaline) in honey has been developed. Samples were dissolved in 30% sodium chloride and then extracted with dichloromethane. The extracts were cleaned up on a Sep-Pak Florisil cartridge. The LC separation was performed on a LiChrosphere RP-18e column (250 x 4.0 mm id) with 0.05M sodium dihydrogen phosphate-acetonitrile (2 +1) as the mobile phase; the drugs were detected at 275 nm with 0.04 AUFS. The calibration graphs were rectilinear from 1 to 40 ng for each drug. The recoveries at the level of 0.5 µg/g were 62.1-90.2%, and the detection limits were 0.05 µg/g for each drug. Sulfamonomethoxine was found in 2 samples of domestic products at levels of 0.23 and 0.83 µg/g.
Liquid Chromatographic Determination of Alprazolam and Related Impurities in the Drug Substance
Authors: Beaulieu Normand , Graham Susan J , Sears Roger W , Lovering Edward G
Published: February 2020

A liquid chromatographic method was developed for the determination of alprazolam and 5 known related compounds in drug raw materials. The method is based on a 3 µm cyano column (100 x 4.6 mm), a mobile phase of 0.01% phosphoric acidacetonitrile- methanol (6 + 3 +1), a flow rate of 1.5 mL/min, and detection at 230 nm. The method resolves the related compounds from the drug and from each other. The limit of quantitation for the impurities in drug raw material is less than 0.1%. Impurity levels in 4 drug raw materials were between 0.01 and 0.41 %. The corresponding mean assay values ranged from 98.3 to 100.6%.
Liquid Chromatographic Determination of Fumonisins with 4-Fluoro-7-nitrobenzofurazan
Authors: Scott Peter M , Lawrence Guillaume A
Published: February 2020

Fumonisins B1 and B2 are closely related mycotoxins produced by Fusarium moniliforme, F. proliferatum, and related species. Disadvantages of 2 fluorescence derivatizing reagents currently used for liquid chromatography (LC) are instability of the derivatives (with o-phthaldialdehyde-mercaptoethanol) and formation of 2 peaks (with fluorescamine). 4-Fluoro-7-nitrobenzofurazan (4-fluoro-7- nitrobenz-2-oxa-1,3-diazole; NBD-F) was, therefore, investigated. Although a larger molar excess of this reagent is required for fumonisins than for amino acids, the derivatives formed are moderately stable, and as little as 1 ng fumonisins B1 or B2 can be detected, with a linear response up to at least 50 ng injected. Reversed-phase LC (C18 column) was carried out with a mobile phase of methanol- 0.05M sodium dihydrogen phosphate adjusted to pH 5 (1 -1-1), which was mixed with an equal volume of acetonitrile-water (8 + 2) after 5 min. Using a modification of a strong anion exchange cleanup procedure, good recoveries (averages of 94 and 80%, respectively) of fumonisins B1 and B2 from ground corn, corn meal, and corn flakes in the 125̶ 5000 ng/g range were generally obtained; the limit of detection of the overall method was about100 ng/g. Similar results were obtained in studies with ground corn, corn meal, and corn flakes using naphthalene-2,3-dicarboxaldehyde-potassium cyanide (NDA-KCN) for derivatization; average recoveries of fumonisins B1 and B2 were 94 and 83%, respectively.
Diphasic Dialysis: A New Membrane Method for a Selective and Efficient Extraction of Low Molecular Weight Organic Compounds from Aqueous Solutions
Authors: Dominguez Lucas , Blanco Jose L , Moreno Miguel A , Diaz Susana D , Prieta Javier , Cámara, José M , Bayo Javier , Suárez Guillermo
Published: February 2020

A new membrane technique is described for the extraction of low molecular weight organic compounds from a wide range of substrates. With this system, the organic compounds of interest contained in the sample pass through the membrane toward the organic solvent, while other substances of higher molecular weight are excluded by the membrane. This procedure allows the extraction or the elimination of toxic substances with a yield of 90%.
Indirect Competitive Enzyme Immunoassay for Tetrodotoxin Using a Biotin-Avidin System
Authors: Matsumura Kendo , Fukiya Sadako
Published: February 2020

An indirect competitive enzyme immunoassay was developed to determine tetrodotoxin (TTX). Antiserum against TTX was demonstrated in rabbits immunized with TTX-keyhole limpet hemocyanin conjugate. In this assay, TTX-bovine serum albumin was coated on the microtiter plate, which was incubated with standard TTX and biotinylated immunoglobulin G from antiserum. The amount of antibody bound on the surface of wells was determined by the reaction of avidin-peroxidase conjugate with its substrate. The minimal detection level of TTX ranged from 5 to 25 pg/assay. The standard curve was linear between 0.25 and 50 ng/assay. A good correlation (r= 0.974) for TTX was also obtained between this indirect competitive enzyme immunoassay and the mouse bioassay.
Liquid Chromatographic Determination of Folic Acid in Infant Formula and Adult Medical Nutritionals
Authors: Jacoby Bart T , Henry Franklin T
Published: February 2020

A liquid chromatographic method for the determination of pteroylglutamic acid (folic acid) in infant formula and liquid medical nutritional diets is described. Extraction of folic acid from the sample matrix is facilitated by a partial enzymatic digestion of the sample proteins. An aliquot of the sample preparation is injected onto a strong anion exchange column (SAX) for preliminary separation, using a pH 5.3 mobile phase of 0.02M sodium acetate and 0.02M sodium sulfate. Before the elution of the folic acid from the SAX column, the eluant is directed onto an octyl bonded-phase column (C8) by using automated switching valves. After the folic acid has been transferred to the C8 column, the SAX column is removed from the flow path. The folic acid is eluted from the Cs column by using an acetonitrile gradient. Detection is by absorption at 345 nm. The mean coefficient of variation is 3.6%, and the range of the recoveries of added folic acid is 95.5-100.2%. The method detection limit and method quantitation limit for infant formula are 10 and 28 µg/kg, respectively. This method is used routinely for the determination of folic acid in infant formula and liquid medical nutritional diets.
Identification and Quantitation of Panthenol and Pantothenic Acid in Pharmaceutical Preparations by Thin-Layer Chromatography and Densitometry
Authors: Nag Saurendra S , Das Saroj K
Published: February 2020

A rapid, simple, and specific thin-layer chromatographic (TLC) method has been developed for the estimation of panthenol and pantothenic acid in pharmaceutical preparations containing other vitamins, amino acids, syrups, enzymes, etc. The vitamin is extracted with ethanol (tablets and capsules) or benzyl alcohol (liquid oral preparations) and isolated from other ingredients by TLC on silica gel with isopropanol-water (85 + 15, v/v) as developing solvent. β-Alanine (pantothenate) or β-alanol (panthenol) is liberated by heating for 20 min at 160°C. The liberated amines are visualized by ninhydrin reaction and estimated by spectrodensitometry at 490 nm. Recoveries for panthenol and pantothenic acid were 99.8 ± 2.25% and 100.2 ± 1.7%, respectively.
Determination of Milk Proteins by Capillary Electrophoresis
Authors: Chen Fu-Tai A , Zang Ji-Hong
Published: February 2020

The potential utility of capillary electrophoresis (CE) for routine determination of milk protein is established. Proteins in cow's milk can be determined by CE in 10 min with high separation efficiency. The major protein components of milk are well-separated and identified. Separations of milk proteins are achieved reliably and reproducibly in an untreated fused-silica column of 21 µm id x 23- 25 cm. Fresh homogenized, low-fat, and nonfat milk show almost identical contents of each protein species; dry milk has a substantially reduced amount of whey proteins, especially oc-lactalbumin. Extensive degradation of whey proteins is evident from a reconstituted dry milk, which may be used to differentiate dry from fresh milk. By using the ratio of β-casein to α-lactalbumin, the adulteration of fresh milk with 25% or more of dry milk could easily be detected.
Determination of Type A and B Trichothecenes in Cereals
by Gas Chromatography with Electron Capture Detection
Authors: Möller Tord E , Gustavsson Håkan F
Published: February 2020

A quantitative method has been developed for determination of nonmacrocyclic trichothecenes in cereals. The mycotoxins are extracted with acetonitrile- ethyl acetate-water, and the extracts are quickly defatted with hexane and purified on a Sep- Pak Florisil cartridge. The trichothecenes are then silylated with Tri-Sil/TBT and quantitated by capillary gas chromatography with electron capture detection. High recoveries of 13 tested trichothecenes were achieved in experiments on wheat at the 250 μg/kg level. The method was also tested on barley, maize, oats, and rye with good results
Assay of Oxytetracycline in Animal Feed by Liquid Chromatography and Microbiological Plate Assay
Authors: Hasselberger Mary Lee
Published: February 2020

In a proposed method for determining oxytetracycline (OTC) in animal feed, OTC is extracted with acidic methanol, and the extract is centrifuged and assayed by microbiological plate assay and by reversed- phase liquid chromatography (LC). Riboflavin and furazolidone elute at retention times similar to that of OTC. Successful separations are made by using both dimethylformamide and acetonitrile mobile phases. Variation between microbiological and LC results is comparable with variation within the microbiological assay. The relative standard deviation for 6 replicates of feed at the 100 ppm level is 3.6% for the LC assay and 3.1% for the microbiological assay.
Extraction of Light Filth from Tofu: Collaborative Study
Authors: Nakashbma Marvin J ,   Collaborators:, Hajoway J M , Keizer H , McGary E D , Senff W A , Silva M L , Spurlock L F , Stenske M A , Torn A , Wheeler M
Published: February 2020

Results are reported for a collaborative study of a method for the extraction of light filth from tofu. A 100 g test portion is digested in HCI solution with Igepal CO-730 and Igepal DM-710. Hairs and insect fragments are isolated by wet-sieving on a No. 230 sieve, dispersing remaining residual product with Aerosol OT 75%, and filtering. Average recoveries by 9 collaborators for 3 spike levels of rat hairs (5, 10,15) were 80,78, and 84%, respectively; for 3 spike levels of insect fragments (5,15,30), recoveries were 97,99, and 99%, respectively. The method was adopted first action by AOAC International.
New Metrological Characteristics of Analytical Methods of Analysis Used for Safety Control of Food and Environmental Materials
Authors: Skurikhin Igor M
Published: February 2020

MQS and MQSm are new metrological characteristics of the limit of determination of methods used for safety control of foods and environmental objects. MQS is the minimum quantity of an analyte that can be determined by any applicable method in an analytical sample. MQSm is the minimum quantity of analyte that can be measured in the test solution in an interlaboratory, method-performance study of a specific method, under the condition that MQSm ≤ MQS. Examples are given of their calculation and use.
Determination of Acesulfam-K in Foods
Authors: Prodolliet Jacques , Bruelhart Milene
Published: February 2020

A liquid chromatographic method was evaluated for the determination of the intense sweetener acesulfam-K in tabletop sweetener, candy, soft drink, fruit juice, fruit nectar, yogurt, cream, custard, chocolate, and biscuit commercial preparations. Samples are extracted or simply diluted with water and filtered. Complex matrixes need a clarification step with Carrez solutions. An aliquot of the extract is analyzed on a reversed-phase μBondapak C18 column using 0.0125M KH2PO4 (pH 3.5)-acetonitrile (90 + 10) as mobile phase. Detection is performed by UV absorbance at 220 nm. Recoveries ranged from 95.2 to 106.8%. With one exception, all analyzed values were within ±15% of the declared levels. The repeatabilities and the repeatability coefficients of variation were, respectively, 0.37 mg/100 g and 0.98% for products containing less than 40 mg/100 g acesulfam-K and 2.43 mg/100 g and 1.29% for other products. The same procedure also allowed detection of many food additives or natural constituents, such as other intense sweeteners, organic acids, and alkaloids, in a single run without interfering with acesulfam-K. The method is simple, rapid, precise, and sensitive; therefore, it is suitable for routine analyses.
Determination of Aspartame and Its Major Decomposition Products in Foods
Authors: Prodolliet Jacques , Bruelhart Milene
Published: February 2020

A liquid chromatographic procedure already evaluated in a preceding study for the analysis of acesulfam-K is also suitable for the determination of the intense sweetener aspartame in tabletop sweetener, candy, fruit beverage, fruit pulp, soft drink, yogurt, cream, cheese, and chocolate preparations. The method also allows the determination of aspartame’s major decomposition products: diketopiperazine, aspartylphenylalanine, and phenylalanine. Samples are extracted or diluted with water and filtered. Complex matrixes are centrifuged or clarified with Carrez solutions. An aliquot of the extract is analyzed on a reversed-phase μBondapak C18 column using 0.0125M KH2P04 (pH 3.5)-acetonitrile ([85 + 15] or [98 + 2]) as mobile phase. Detection is performed by UV absorbance at 214 nm. Recoveries ranged from 96.1 to 105.0%. Decomposition of the sweetener was observed in most food samples. However, the total aspartame values (measured aspartame + breakdown products) were within -10% and +5% of the declared levels. The repeatabilities and the repeatability coefficients of variation were, respectively, 1.00 mg/100 g and 1.34% for products containing less than 45 mg/100 g aspartame and 4.11 mg/100 g and 0.91 % for other products. The technique is precise and sensitive. It enables the detection of many food additives or natural constituents, such as other intense sweeteners, organic acids, and alkaloids, in the same run without interfering with aspartame or its decomposition products. The method is consequently suitable for quality control or monitoring.
Automated Technique for Sampling Milk from Farm Bulk Tanks: Collaborative Study
Authors: Packard Vernal S , Ginn Roy E , Metzger Dick T
Published: February 2020

An automated, in-line, mechanical technique for sampling milk from farm bulk tanks was evaluated in a collaborative study. The automated sampling device, which is mounted on the milk intake line, contains an electronically controlled peristaltic pump. The device takes a representative sample of the entire volume pumped through the system. Samples taken can be analyzed for both composition and microbiological quality. The study was performed in 3 phases. In the first 2 phases, samples taken by manual and automated methods were compared in analyses for somatic cell count, antibiotics, fat, protein, lactose, and solids-not-fat. The third phase, using a modified procedure, was designed to compare sampling methods in analyses for total bacteria count (standard plate count), psychrotrophic bacteria count, and coliform count. Evaluation of the data by a nested ANOVA indicated no difference between results for samples taken by the automated and manual methods (P = 0.05) in Phases 1 and 2, irrespective of whether the bulk milk was agitated before sampling. By introducing a sanitizing step between farms in Phase 3, the automated method also provided samples comparable with those taken manually for microbial analyses. The automated method has been adopted first action by AOAC International.
Analysis of Testosterone Esters by Tandem Mass Spectrometry
Authors: Cairns Thomas , Siegmund Emil G , Rader Bobby
Published: February 2020

The electron ionization (El) and chemical ionization (CI) mass spectra of 12 representative testosterone esters were examined to explore the various analytical options available for identification and confirmation of the esters. Using El, a number of fragment ions indicated the identification of the testosterone moiety, but structural confirmation of the individual esters often required the observance of the molecular ion at very low relative abundance ratios. The acceptable analytical method involved CI/tandem mass spectrometry based on the production of the 2 generic product ions derived from the protonated molecule ion.
Liquid Chromatographic Assay of Bentazon Formulations
Authors: Schmitt Thomas M
Published: February 2020

A reversed-phase liquid chromatographic method is presented for determining the active agent in technical bentazon and in aqueous formulations of the sodium salt of bentazon. The procedure is an isocratic, external standard method specifying an octadecylsilyl column, an acetate-buffered mobile phase of methanol-water, and UV detection. The 340 nm detection wavelength eliminates interference from formulation impurities.
Niacin I: Dissolution Profiles of Sustained-Release Niacin Products by Automated and Manual Procedures
Authors: Kirchhoefer Ross D , Hipp Sharon
Published: February 2020

Automated and manual procedures were developed to obtain dissolution profiles of sustained-release niacin formulations. The procedures are based on the United States Pharmacopeia XXII apparatus 1 (basket) at 100 rpm with 900 mL 0.1 N HCI as the dissolution medium. Filtered aliquots are read at 260 nm. No interference was found from excipients. The procedures are straightforward and will discriminate between sustained-release and regular niacin formulations.
Analysis of Milk-Based Infant Formula. Phase V. Vitamins A and E, Folic Acid, and Pantothenic Acid: Food and Drug Administration-Infant Formula Council: Collaborative Study
Authors: Tanner James T , Barnett Stephen A , Mountford Mardi K ,   Collaborators:, Angyal G , Beare-Rogers J L , Boyer K W , Bueno M P , DeAngelis N , DeVries J W , Dube D , Ellefson W , Fisher P , Landen W O , Navis J , Pearson D , Reynolds S L , Richards P , Soliman A-G , Thompson J N , Thomson W
Published: February 2020

In 1982, the U.S. Food and Drug Administration, the Infant Formula Council and its member companies, contract laboratories, and other government laboratories began a study of analytical methods for the nutrients listed in the Infant Formula Act of 1980 (P.L. 96-359). Four phases of the study have been completed and are discussed in earlier reports. The present report provides data on Phase V, in which 13 laboratories collaboratively studied individual methods for folic acid, pantothenic acid, and vitamin E, in addition to 2 methods for vitamin A. Vitamins A and E are determined by liquid chromatography. Folic acid and pantothenic acid are determined by microbiological methods using acidimetric and/or turbidimetric assays as the determinative step. In most cases, relative standard deviations for repeatability, RSDr, and reproducibility, RSDR, are as good as those that would be predicted from other collaborative studies. RSDr and RSDR values obtained for the 5 methods are 9.35 and 25.44% for folic acid, 4.59 and 10.23% for pantothenic acid, 8.46 and 11.69% for vitamin E, 3.62 and 9.72% for vitamin A (retinol isomers), and 4.9 and 10.5% for vitamin A (retinol). The 5 methods have been adopted first action by AOAC International.
Sample Preparation Bias in Carbon Stable Isotope Ratio Analysis of Fruit Juices and Sweeteners
Authors: Krueger Dana A
Published: February 2020

Two sample preparation methods are commonly used for carbon stable isotope ratio analysis (SIRA). One involves combustion of the sample with oxygen at 850° C the other involves combustion of the sample with CuO in an evacuated glass tube at 550°C. I observed in our laboratory that these 2 methods yield different results for sugarbased products such as fruit juices, sweeteners, and vanillin. The CuO method yields results approximately 1© more positive than the oxygen combustion method. This bias is also observed in other laboratories, as shown in an analysis of the results of the AOAC collaborative studies of carbon SIRA of maple syrup, orange juice, honey, and honey protein. The oxygen combustion method is the AOAC method for honey, apple juice, and orange juice; both methods are incorporated into the AOAC method for maple syrup. I recommend that data generated by the CuO combustion method be appropriately corrected to yield results concordant with the official oxygen combustion method.
Stability-Indicating Proton Nuclear Magnetic Resonance Spectroscopic Assay Method for Furosemide in Tablets and Injections
Authors: Hanna George M , Lau-Cam Cesar A
Published: February 2020

A simple, specific, and accurate proton nuclear magnetic resonance (1H-NMR) spectroscopic method has been developed for the identification and assay of furosemide and its degradation product, 4-chloro-5-sulfamoylanthranilic acid (CSA), in tablets and injections. Dissolution of the sample in D20-NaOD resulted in a solution yielding the required separation among the resonance signals of furosemide, CSA, and ferf-butyl alcohol, the internal standard. The mean ± SD recovery values of furosemide and CSA from 10 synthetic formulations were 99.6 ± 0.8 and 98.9 ± 1.7%, respectively. Commercial tablets (6 lots) and injections (5 lots) of furosemide were assayed by the proposed method and found to contain 53.1-99.8% furosemide and 0.3-45.2% CSA.
Carboxylic Acid Composition of Authentic Varietal and Commercial Grape Juices
Authors: Fuleki Tibor , Pelayo Estela , Palabay Rodrigo B
Published: February 2020

Quantities were determined of tartaric, malic, citric, lactic, succinic, and shikimic acid present in juices produced by cold and hot pressing from 56 grape cultivars grown in Ontario for the 1988 and 1989 seasons. The individual acids were separated by liquid chromatography (LC) and detected at 210 or 250 nm. Lactic and succinic acids were determined enzymatically. The ranges of acid concentrations found were as follows: tartaric, 4.19-13.51 g/L; malic, 1.68-15.36 g/L; citric, 0.305-1.158 g/L; lactic, 0.015-0.388 g/L; succinic, 0.002-0.075 g/L; and shikimic, 0-0.102 g/L. Tartaric and malic acids were the major acids in every cultivar. The tartaric:malic acid ratio ranged from 0.52 to 4.36, but it was >1.0 in most cases. Genotype had significant effect only on the shikimic acid content. Hot pressing of red cultivars yielded juice with significantly higher pH and tartaric, citric, lactic, and total acid contents than cold pressing. Vintage had no significant effect on acid composition. The total acid content determined by LC was always considerably higher than the titratable acidity, but good correlation existed between the 2 measurements. Most commercial grape juice had similar composition to that of authentic juices. However, tartaric acid content was lower in the majority of commercial juices because of losses during the detartration process. Also, indications of acidulation existed in some of the commercial juices.
Hydroxyamidines as New Extracting Reagents for Spectrophotometric Determination of Cadmium with 4-(2-Pyridylazo)naphthol in Industrial Effluents, Coal, and Fly Ash
Authors: Chakravarty Sumon , Deb Manas Kanti , Mishra Rajendra Kumar
Published: February 2020

A simple, sensitive, and selective extractive spectrophotometric method for the determination of cadmium in trace quantities with N1-hydroxy-N1,N2- diphenylbenzamidine (HDPBA) and 4-(2-pyridylazo) naphthol (PAN) is described. The method is based on the extraction of cadmium with HDPBA into chloroform at pH 9.0 ± 0.2 and simultaneous spectrophotometric determination wiith PAN. The binary Cd(ll)-HDPBA complex extracted into chloroform has a molar absorptivity of 1.96 x 104L/ mol/cm at λmax 400 nm. The sensitivity of the yellow Cd(ll)-HDPBA complex was increased remarkably by the addition of PAN to the binary complex. With 6 different hydroxyamidines tested, the red-orange complex in chloroform exhibited maximum absorbance at 530-550 nm, with molar absorptivity values of 3.2-5.6 x 104L/mol/cm. The method adheres to Beer’s law up to 1.5 μg cadmium/mL organic phase. The detection limit of the method is 0.02 μg Cd/mL. Investigations of the effect of foreign ions revealed that the present method is free from matrix interference of most of the common ions (e.g., Fe(lll), Ni(ll), Cu(ll), Mn(ll), V(V), Co(ll), Al(lll), Cu(ll), Mg(ll), and Mo(VI)). The relative standard deviation for 10 repetitive analyses of the metal was 1.4%. The validity of the method was tested successfully with various environmental samples.
Liquid Chromatographic Determination of RH-5992, an Ecdysone Agonist, in Some Forestry Matrixes
Authors: Sundaram Kanth Maran Somu , Jiusheng Zhu , Nott Reginald
Published: February 2020

A liquid chromatographic method is described for the analysis of RH-5992 (N'-t-butyl-N'-[3,5-dimethylbenzoyl]- N-[4-ethylbenzoyl] hydrazine) from various terrestrial and aquatic forestry matrixes and stream water. The processed soils, Hitter, oak foliage, sediment, aquatic plants, and fish were extracted with a mixture of acetone and water; balsam fir needles were extracted with acidified methanol solution; stream water was extracted with dichloromethane. Aliquots of crude extracts were solvent partitioned, concentrated, and cleaned up by using Florisil or Prepsep-NH2 columns. After fractional elution of the columns with hexane-ethyl acetate as the eluent, the eluates were analyzed on a liquid chromatograph equipped with a diode-array UV detector set at 236 nm, using an RP-8,10 μm column with a mobile phase of acetonitrile- dioxane-water. Fir needles required methanol in addition to the 3 solvents in the mobile
Influence of Water on the Near Infrared Spectra of Model Compounds
Authors: Reeves III James B
Published: February 2020

The application of near infrared spectroscopy (NIRS) to high-moisture samples (i.e., silages) has shown that accuracy does not match that of dried materials. Examination of spectra does not indicate absorbance levels to be the problem. The objective of this effort was to determine the effect of water on the spectra of model compounds. Near infrared spectra were taken using a Digi-Lab FTS-65 Fourier transform spectrometer. Liquids were examined by transmission and solids by reflectance. Examination of organic acids, alcohols, ketones, amines, and amides showed that the presence of water causes shifts in spectral wavelengths not related to OH or NH groups. The most significant shifts were for alcohols and ketones (up to 10+ nm at 90% H2O) and least for acids. These peak shifts increased with increasing amounts of water and varied within individual spectra and among the compounds tested. As solids, sugars and amino acids had many sharp peaks in their spectra. As solutions, however, the sharp spectral features disappeared, resulting in large broad peaks. The spectra of polymers such as starch, cellulose, and casein did not appear to be significantly altered by the presence of water (0-50%, w/w), although they often appear to alter the water spectra. Variations in water content, physical state, and concentrations of components, when combined with these results, may help
Determination of Metals in Foodstuffs by Atomic Absorption Spectrophotometry after Dry Ashing: NMKL Interlaboratory Study of Lead, Cadmium, Zinc, Copper, Iron, Chromium, and Nickel
Authors: Jorhem Lars ,   Collaborators:, Afthan G , Cumont G , Dypdahl H P , Gadd K , Havre G N , Julshamn K , Kaverud K , Lind B , Loimaranta J , Merseburg M , Olsson A , Piepponen S , Sundstrom B , Uppstad B J , Waaler T , Winnerstam L
Published: February 2020

An interlaboratory study of a method for determination of lead, cadmium, zinc, copper, iron, chromium, and nickel in foodstuffs by atomic absorption spectrophotometry (AAS) after dry ashing at 450°C was conducted in 16 laboratories. The study was preceded by a practice round of familiarization samples and another round in which solutions were distributed and the metals were determined directly by AAS. The study included 5 different foods (liver paste, apple sauce, minced fish, wheat bran, and milk powder) and 2 composite diets. A single analysis was carried out on each sample. Suitable sample combinations were used as split level combinations for determination of the repeatability standard deviation. The relative reproducibility standard deviation for each of the elements ranged as follows: lead, 74-18% at 0.025-0.28 mg/kg; cadmium, 80-11% (0.002-0.51 mg/kg); zinc, 12-7% (44- 72 mg/kg); copper, 47-10% (0.48-41 mg/kg); iron, 35-9% (2-228 mg/kg); chromium, 48-21 % (0.008- 0.22 mg/kg); nickel, 64-39% (0.025-0.39 mg/kg).
Determination of Formaldehyde in Fresh and Retail Milk by Liquid Column Chromatography
Authors: Kaminski Jerzy , Atwal Avtar S , Mahadevan Subramaniam
Published: February 2020

A quantitative method is described for the determination of formaldehyde (CH2O) in milk by liquid chromatography. Aldehyde derivatization-extraction was carried out in situ with 2,4-dinitrophenylhydrazine in 2-phase reaction medium. Average recovery of added CH2O (0.1 μg/mL) was 89.9 ± 3.9% with an estimated detection limit of 0.009 mg/kg. The technique was used for the determination of CH2O in commercial 2% milk and in fresh milk of cows fed on a typical North American dairy diet. The average concentrations of CH2O in fresh and commercial milk were 0.027 and 0.164 mg/kg, respectively. Several methods for CH2O determination in milk are compared.
Methyl Bromide Determination in Selected Foods by Headspace Technique
Authors: Daft James L
Published: February 2020

A headspace method used earlier for determining methyl bromide (MB) in assorted nuts and peanut butters has been successfully applied to other foods that could potentially contain traces of this toxic fumigant. The foods tested include 63 off-theshelf spices and seasonings, 83 table-ready items (grain-based, dried, or highly seasoned), 30 dried fruits and trail mixes, and 38 oil-based items (oilseeds, cooking oils, or spicy oil-based dressings). Sample headspace gas is produced by blending ≤50 g sample in 250±50 mL aqueous solution in a sealed 1000 mL blender cup. After equilibration at 25C, the headspace is sampled with a gas-tight syringe and injected into a dual column-dual detector gas chromatograph. One determination is made with a 20% OV-101 packed column and a 63Ni electron capture detector (ECD), the other with a GS-Q wide-bore capillary column and a Hall electrolytic conductivity detector (HECD). Of the approximately 200 samples tested, none contained detectable MB residue at a quantitation limit <100 ng/g sample. All fortified samples yielded MB recovery. Samples were fortified at levels ranging from 78 to 3250 ng MB/g. Recoveries ranged from a mean high of 56% for spices and seasonings to a mean low of 30% for oil-based foods. The overall recovery and CV, including the results from assorted nuts and peanut butters, were 46 and 33%, respectively.