Wet Ashing Procedures Research Articles

Manganese quantification in some Egyptian food items using inductively coupled plasma optical emission spectroscopy

ABSTRACT The current study was conducted to measure the manganese content in nine different food groups. A cross-sectional study was designed; a total of 89 food items were randomly purchased from the main markets and hypermarkets in Alexandria Governorate, then digested by wet ashing procedure and finally analyzed using ICP-OES. The highest mean Mn value was obtained in the fat group (6.75 µg/g) compared to the other eight groups, followed by nuts (4.64 µg/g) and the protein-rich food group (4.52 µg/g), while meat and its products have the lowest mean of Mn (0.53 µg/g). Manganese content in food groups is strongly correlated with the food matrix, soil composition, and fortification process. Local butter, margarine, sunflower oil, corn oil, Scomberomorus commerson, poulty fish, pistachio, and walnuts had the highest content of manganese.

Quantitative determination of selenium in the most common food items sold in Egypt

Particular interest in selenium (Se) was generated as a result of clinical studies showing that balanced Se dietary system is very important for many physiological processes. There is no recent information available on the Se content in Egyptian foods. The present study was conducted to measure Se content in different food groups. A cross-sectional study was designed; a total of 87 food items were randomly purchased from the main markets and hypermarkets in Alexandria governorate, then digested by wet ashing procedure and finally analyzed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The highest mean Se value was obtained in protein-rich food followed by nuts and sweetened products (6.8, 6.2, and 5.89 μg/g respectively) shrimps had the highest value among all studied samples (6.8 μg/g), while the lowest one was in soft cheese (0.0036 μg/g). Selenium content in food groups is strongly correlated with food matrix and composition of food items, soil composition, and fortification process.

Intra- and inter-individual variability of stable strontium isotope ratios in hard and soft body tissues of pigs.

Stable isotope analysis has become an indispensable tool for the identification of the flow of matter in ecological sciences. Stable strontium isotope ratios are used in several different scientific fields as markers for provenance, mobility, and migration. A crucial prerequisite for such studies is a reliable definition of local ranges and an estimation of expected isotopic variability. To study the local variability of stable strontium isotope ratios at a specific place, a farrow of ecologically and locally grown pigs was investigated and strontium was extracted from their hard tissues (tooth enamel, bones and bristles) as well as soft tissues (meat, organs and blood) via dry- and wet-ashing procedures and subsequent column separation. The 87 Sr/86 Sr ratio was then measured via TIMS (thermal ionization mass spectrometry). Reliable 87 Sr/86 Sr data was generated from all tissue types. Both intra- and inter-individual variability was high and tissue-specific patterns could be identified. High ranges occurred in sample types which were analyzed for animals of different age (pigs as well as piglets): teeth, parietal, mandible, femur, and leg muscle as well as in jaw muscle samples, which were only analyzed in adult pigs. Tooth enamel data showed a tooth-type-dependent pattern. We conclude that a time factor played a role for the observed variability, e.g. a shift in food supply. Furthermore, we presume that local range estimates from the literature only work for tissues which integrate all consumed components over a sufficient amount of time and average fluctuations which can be found in tissues with higher turnover rates.

Chronic Transfusion and Iron Overload Modify the Mouse Gut Microbiome

BACKGROUND: Although iron is an essential element in critical metabolic pathways of both pathogenic microorganisms and their hosts it is less essential in certain barrier bacteria, such as Lactobacilli. Dietary iron supplementation increases mortality and affects the microbiome in African children, decreasing the abundance of beneficial Lactobacilli. Furthermore, the method of iron repletion influences the microbiome in patients with inflammatory bowel disease.AIM: To determine whether iron status and different methods of iron supplementation/overload affect the gut microbiome in mice.METHODS: Cohorts of iron-deficient, iron-replete, and iron-overloaded wild-type C57BL/6 female mice (n=5 per group) were generated by dietary manipulation and by injection of iron dextran (0.3mg weekly x 6) or RBC transfusion (0.3mL at 60% hematocrit weekly x 6). The day after the last injection/transfusion, mice were sacrificed and tissues (blood, liver, spleen, and duodenum) and feces, from the cecum and rectum, were collected. Iron levels in tissues and in rectal feces were quantified by a wet ashing procedure. Commercial ELISA kits were used to quantify circulating hepcidin and ferritin levels. DNA from feces was extracted using the Fecal DNA extraction kit (Mo Bio) and sent to the Molecular Research (MRDNA) center for 16S rDNA Illumina platform sequencing and analysis. Statistical analyses were performed using LEfSe database (https://huttenhower.sph.harvard.edu/galaxy/) and GraphPad Prism.RESULTS: Mice fed an iron-deficient diet from weaning developed iron deficiency anemia with decreased intracellular iron stores, as measured by serum ferritin and liver and spleen iron (see Table). Iron dextran injections induced iron overload in mice fed either an iron deficient or iron replete diet. Chronic transfusion induced iron overload in mice fed an iron replete diet, but led to iron repletion without overload in mice fed an iron deficient diet. The iron deficient diet decreased, whereas the iron supplemented diet increased, fecal iron significantly. Although, iron dextran injections and chronic transfusion increased hepcidin levels, they did not significantly affect fecal iron. Analysis of microbiome data showed that fecal iron modulated the relative abundance of different bacteria. The phylum Proteobacteria showed a negative trend with increasing fecal iron associated with decreasing relative abundance (R2 0.5; p<0.006), Firmicutes showed a positive trend with increasing fecal iron associated with increasing relative abundance (R2 0.3; p<0.02), whereas the phylum Bacteroidetes did not show a significant association. Within the phylum Firmicutes, fecal iron concentration was a reasonable predictor of family Lactobacillaceae abundance (R2 0.5; p=0.005), with increasing iron reducing the relative abundance; in contrast, increasing iron was associated with increased relative abundance of family Clostridiaceae (R2 0.7; p<0.0001). We next investigated whether iron dextran infusions, chronic transfusions, or oral iron supplementation modulated microbiome composition. Analysis of the families belonging to class Clostrida showed that family Clostridiaceae increased with an iron supplemented diet, iron dextran infusions, or transfusional iron overload; family Eubacteriaceae increased with iron dextran and blood transfusions, but not with the iron supplemented diet, and family Peptococcaceae only increased with iron dextran treatment. These results suggest that different methods of iron supplementation or overload affect families in the class of Clostrida differently. Finally,comparisons of the cecal and rectal microbiomes did not identify any substantial differences.CONCLUSIONS: In this study, iron status modified the microbiome in mice. The microbiome was further modulated by different types of iron overload, especially in the class Clostrida. Similar to human studies, increasing fecal iron decreases the abundance in the gut of potentially beneficial lactobacilli. Although there are differences between mouse and human gut microbiomes, this mouse model can be used to study the effects of iron supplementation strategies and iron overload and can provide the foundation for further studies focused on the role of iron in host-pathogen interactions and immune function. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

COMPARISON OF DRY ASHING, WET ASHING AND MICROWAVE DIGESTION FOR DETERMINATION OF TRACE ELEMENTS IN PERIOSTRACUM SERPENTIS AND PERIOSTRACUM CICADAE BY ICP-AES

The work was to demonstrate a repaid, precise and accurate determination method for ten trace elements (Al, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Se and Zn) in periostracum serpentis (PS) and periostracum cicadae (PC) by inductively coupled plasma atomic emission spectrometry (ICP-AES). In order to evaluate the best digestion method, three different sample digestion methods including dry ashing, wet ashing and microwave digestion procedures were compared in this study. Method validation was carried out through the generation of calibration curves with multi-element standard solutions and a standard addition method by using standard reference material (GBW 07604-Poplar leaves). The results revealed the microwave digestion procedures were the best sample digestion method because of dry ashing and wet ashing procedures without any advantages in terms of digestion efficiency than the microwave digestion procedures. Trace element contents in PS and PC samples presented a wide variability from the test results, and ten trace element contents in PC were found to be higher than in PS. Determination of trace elements by ICP-AES after microwave digestion was more sensitive and precise, which can be used for quality control and analysis of pharmacological effect in various ecdyses of some animal samples.

An improved dry ash procedure for the detection of titanium dioxide in cattle feces

We improved the dry ash procedure for detecting titanium dioxide (TiO2 ) in cattle feces containing chromium oxide [corrected] (Cr(2)O(3) ). First, the effect of amount of sodium sulfate (Na2 SO4 ) on the recovery of TiO2 from cattle feces that contained Cr2 O3 was evaluated. Average recovery of TiO2 at the 2.5 g Na2 SO4 level was significantly higher (P < 0.0001) than that at 0.75 g Na2 SO4 . Second, the effect of Cr2 O3 concentration on the recovery of TiO2 of cattle feces by using two levels of Na2 SO4 addition was examined. The recovery of TiO2 decreased with the increase in the amount of Cr2 O3 at the 0.75 g Na2 SO4 level but was consistently high at 2.5 g Na2 SO4 . Third, the recovery of Cr2 O3 from cattle feces was checked. The recoveries of TiO2 and Cr2 O3 were high enough at the 2.5 g Na2 SO4 level. Fourth, the improved dry ash procedure (5 mL of concentrated H2 SO4 and 2.5 g of Na2 SO4 were used for sample digestion) was compared to the wet ash procedure. Average recovery of TiO2 by the improved dry ash procedure was significantly higher (P = 0.0077) than that by the wet ash procedure. Thus, the improved dry ash procedure can be used for TiO2 analysis in cattle feces containing Cr2 O3 .

Aspects on the analysis of 210Po

There has been little development regarding analysis of polonium (Po) in environmental samples since the 1960ies. This is due to the straightforward spontaneous deposition of this element on silver (Ag), nickel (Ni) or copper (Cu) without any radiochemical separation. For many years, no radiochemical yield determinant was used and it was generally supposed that the yield was 100% after two depositions. Counting was often done using ZnS scintillation counter coupled to a photomultiplier tube. However, the use of the yield determinants 208Po and 209Po and the development of alpha spectrometry showed that the yield was lower. Furthermore, the tendency of Po to volatilize at low temperatures constrains the sample preparation techniques; dry-ashing cannot be used. But during the wet-ashing procedure, there are still some losses. The aim of this study was to evaluate the Po losses during wet-ashing by the use of a double-tracer technique. We have found that the losses were about 30% when open glass beakers were used and about 17% when the samples were digested in microwave oven. When long-necked bottles (Kjeldahl flasks) were used, a loss of about 20% was registered. It has also been observed that 210Pb to some extent is plating out together with its daughter nuclide Po during the electrochemical deposition. This will result in a systematic error since an unknown amount of supported 210Po will be produced from the 210Pb decay depending on the fraction of 210Pb being deposited on the disc and the waiting time between deposition and measurement of the sample. A further consequence of this is that in the assessment of the 210Pb content in the sample, very often the remaining liquid is stored after deposition for build-up of 210Po. Since some 210Pb is lost on the disc, the result for 210Pb will be too low. Both these systematic errors give rise to a too high 210Po/ 210Pb ratio. The fraction of 210Pb which is plating out has been assessed in this study for different matrices and is about 50–90%. During the measurement by solid state Si-detectors, some Po is evaporated in the vacuum conditions contaminating the detectors. Experiments have here been done by heating the discs after deposition which indicate that less Po is evaporated from Ag than from Ni. The losses from Ag are less than that from the other metals probably due to a deeper penetration into the surface of Po. We conclude that in most aspects, Ag is better to use than the other plating metals.

Investigation of heavy-metal uptake by vegetables growing in contaminated soils using the modified BCR sequential extraction method

The heavy metal (Cu, Fe, Co, Ni, Cd, Cr, Pb, Zn, and Mn) concentrations in soils and in vegetable samples, i.e. lettuce (Lactuca sativa L.), parsley (Petroselinum crispum), dill (Anethum graveolens), and onion (Allium cepa L.), taken from three urban vegetable gardens in Kayseri, Turkey, were determined by FAAS. The modified three-step sequential extraction procedure proposed by the European Bureau of References (BCR), now the Standards, Measurements and Testing Programme, was used in order to evaluate trace elements mobility in soil samples, and heavy-metal uptake by vegetables. Three operationally defined fractions were isolated using the BCR procedure: acid extractable (i.e. bound to carbonates), reducible (bound to Fe/Mn oxides), and oxidizable (bound to organic matter and sulphides). The vegetable samples were prepared to analysis using the wet-ashing procedure. To estimate the accuracy of the method used in analysis of the vegetable samples, the standard reference material (NIST SRM 1573a, Tomato leaves) was used. The results of recovery for all the elements were relatively satisfactory (87.7–108%). For the soil samples, the recovery values were calculated by proportioning the sum of the steps of the BCR procedure to those of the pseudototal digestion (i.e. aqua regia). In soils, the mobility of heavy metals followed the order Mn>Cd>Cu>Pb>Zn>Cr>Ni>Co>Fe. The relationship between the vegetable–metal and soil–extractable metal concentrations was examined in order to evaluate the bioavailability of metals, and the positive correlation, especially for the first (i.e. water, acid-soluble and exchangeable fraction) and for the third (i.e. oxidizable fraction) extraction steps, was obtained.

Determination of Cu, Pb, Cd, Ni, Cr, Co, Mn, Fe and Zn in algae and vegetable samples using wet and dry ashing procedures

Determination of Cu, Pb, Cd, Ni, Cr, Co, Mn, Fe and Zn in algae and vegetable samples using wet and dry ashing procedures

A comparative evaluation of wet digestion and dry ashing methods for the determination of some major and minor nutrients in composted manure

The analytical results of 53 manure samples determined by wet digestion and dry ashing procedures were compared in order to evaluate their relative suitability for recovering different nutrient elements in manure and manure compost. Wet digestion recovered greater amounts of phosphorus (P), potassium (K), calcium (Ca), manganese (Mn), and zinc (Zn) in more samples than dry ashing. Nutrient contents in the samples were highly variable, with coefficients of variation (CV) ranging from 38% for magnesium (Mg) to 161% for copper (Cu) analyzed by the wet digestion procedure, and from 47% to 138% for Mg and Cu analyzed by the dry ashing procedure. The mean values of P, K, Ca, Mn, and Zn averaged for the 53 samples were significantly higher using wet digestion than dry ashing procedure, but both procedures recovered comparable amounts of iorn (Fe), Mg, and Cu. Correlations analysis between both procedures for each element showed reasonable to fair agreements for Ca (R 2 = 0.93), K (R 2 = 0.93), P (R 2 = 0.90), Mg (R 2 = 0.84), Fe (R 2 = 0.87), Mn (R 2 = 0.73), and Cu (R 2 = 0.66), but poor agreement for Zn (R 2 = 0.44). The low agreement between procedures for Zn suggests that wet digestion, which gave a higher recovery, should be a preferred procedure for analyzing Zn in manures.

Bioavailability of Soil‐Extractable Metals to Tea Plant by BCR Sequential Extraction Procedure

This study principally describes the distribution of the heavy metals such as Cu, Pb, Cd, Co, Cr, Fe, Mn, Ni, and Zn in different soil fractions and different parts of tea plant, and plant availability with single correlation. For this purpose, soil and corresponding plant samples were collected from the three tea gardens in Rize, Turkey. Tea plant (Camellia sinensis), which were segmented into leaf, stem, and root, and also treated black tea samples, were dissolved with both wet and dry ashing procedures. The BCR sequential extraction method was used for extracting the metals bound to target phases in soil samples. The method was performed to extract the metals present in exchangeable and acid soluble (i.e., bound to carbonates), reducible (bound to Fe/Mn oxides), and oxidisable forms (bound to organic matter and sulphides) in the soil samples. The determination of heavy metals in tea and soil samples was performed by FAAS. The results obtained from the sample analysis were compared with their typical soil and plant contents. For determining accuracy of the methods used, recovery studies were done and the results were found to be satisfactory (between 76% and 102%). In order to understand the uptake of metal from soil to tea plant, correlation analysis was performed between the different physicochemical forms of soil metals and their concentrations in tea plant tissues. Correlation analysis results indicated that pseudototal content of the heavy metals in soils and their sum extracted with the sequential extraction procedure were poor indicators for heavy metal uptake by plants. For Cd and Mn elements, significant positive correlations (r = 0.923–0.996) were found between the metal contents in fraction 1 of the sequential extraction procedure for soils and their concentrations in roots, stems, and leaves of the tea plant.

Determination of Zn, B, Fe, Mg, Ca, Na and Si in anisette samples by inductively coupled plasma atomic emission spectrometry

A comparative study of several digestion methods of anisette samples has been carried out. Two dry ashing (DA) treatments as well as four wet ashing (WA) procedures using different mixtures of acids were applied for the sample mineralisation before analysis. Once the anisette samples were mineralised, the contents of Zn, B, Fe, Mg, Ca, Na and Si were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Each method has been studied statistically and also attending to their feasibility. After performing the optimisation of the different treatments tested, it was concluded that one wet ashing method employing a HNO3:H2O2 (10:1) mixture was the most suitable. This method was applied to the analysis of anisette samples. Na, Ca, Mg and Si were present in concentrations up to 215mgl−1 for Na, 11.6 for Mg, 6.2 for Ca and 5.1 for Si. Fe and B concentrations were not higher than 0.12mgl−1 and lower for Zn.

Determination of calcium, potassium, manganese, iron, copper and zinc levels in representative samples of two onion cultivars using total reflection X-ray fluorescence and ultrasound extraction procedure

The chemical characterization of onion cultivar samples is an important tool for the enhancement of their productivity due to the fact that chemical composition is closed related to the quality of the products. A new sample preparation procedure for elemental characterization is proposed, involving the acid extraction of the analytes from crude samples by means of an ultrasonic bath, avoiding the required digestion of samples in vegetable tissue analysis. The technique of total reflection X-ray fluorescence (TXRF) was successfully applied for the simultaneous determination of the elements Ca, K, Mn, Fe, Cu and Zn. The procedure was compared with the wet ashing and dry ashing procedures for all the elements using multivariate analysis and the Scheffé test. The technique of flame atomic absorption spectrometry (FAAS) was employed for comparison purposes and accuracy evaluation of the proposed analysis method. A good agreement between the two techniques was found when using the dry ashing and ultrasound leaching procedures. The levels of each element found for representative samples of two onion cultivars (Yellow Granex PRR 502 and 438 Granex) were also compared by the same method. Levels of K, Mn and Zn were significantly higher in the 438 Granex cultivar, while levels of Ca, Fe and Cu were significantly higher in the Yellow Granex PRR 502 cultivar.

Ultrasonic extraction followed by sonolysis-ozonolysis as a sample pretreatment method for determination of reactive arsenic toward sodium tetrahydroborate by flow injection-hydride generation AAS.

A new sample pretreatment method based on ultrasonic extraction in HCI medium and subsequent oxidation of the extracts by sonozone (i.e., sonolysis-ozonolysis) has been developed for determination of reactive arsenic toward sodium tetrahydroborate [mainly As(III) + As(V)] by flow injection-hydride generation atomic absorption spectrometry. This method avoids the use of intensive treatments with concentrated and corrosive acids, high pressures, and temperatures that are inherent with traditional wet or dry ashing procedures and entails reduced waste production and reagent consumption. A sonozone process at room temperature was optimized to break the bond of As to proteins and macromolecular constituents which was an essential requirement for effective reduction by L-cysteine prior to arsine generation. Spiking experiments showed that As(III), As(V), MMA, and DMA were fully recovered from several matrixes on applying the above treatment. On the other hand, a nonreducible As species such as arsenobetaine that is predominant in some biological samples remained unchanged. Application of the method to sediment, soil, fly ash, and plant CRMs demonstrated that, in general, a good agreement existed between certified and found As contents, thereby indicating the absence of nonreducible As forms. Low As recoveries were observed for fish CRMs, as a result of the nondegradability of arsenobetaine by sonozone. The detection limit of As in the samples investigated was in the range 0.19-2.8 microg g(-1).

Determination of heavy metal contents in human colostrum samples by electrothermal atomic absorption spectrophotometry.

Determination of lead, cadmium, nickel, chromium, manganese and copper levels in colostrum samples (n = 30), collected from middle-class mothers, was carried out by electrothermal atomic absorption spectrophotometer (ETAAS) with Zeeman effect background correction using a tungsten-palladium-citric acid chemical modifier mixture. A wet-ashing procedure was applied to dissolve the samples and to remove the fat. The graphite furnace temperature programme for analytes determined by ETAAS was studied, and the optimum pyrolysis temperatures of Pb, Cd, Ni, Cr, Mn and Cu were determined in the presence of the modifier mixture. Detection limits of Pb, Cd, Cu, Mn and Cr were determined using a modifier mixture solution. Zinc and iron levels were determined by Zeeman flame atomic absorption spectrometer (F-AAS). Heavy metal levels (mean values) found in colostrum samples were 14.6 microg/l of Pb, 2.8 microg/l of Cd, 27.8 microg/l of Ni, 8.6 microg/l of Cr, 43.2 microg/l of Mn, 278 microg/l of Cu, 12.9 mg/l of Zn, and 3.5 mg/l of Fe. These metal levels were compared with results from other studies in different countries.

Effect of method of analysis on iron content of beef from advanced meat recovery systems

A field survey was conducted by the USDA, Food Safety Inspection Service (FSIS) to provide analytical data on meat obtained from beef cervical vertebrae processed by advanced meat recovery (AMR) systems. As a result, an added iron performance standard was proposed to limit the amount of marrow in AMR products. The performance standard was based on iron content of hand boned lean compared to AMR lean. Iron content was determined by a hydrochloric wet ash digestion method. The same samples were then analyzed using dry ash digestion. The objectives of the study were to determine differences in iron content of the survey samples due to the digestion method and the impact of this difference on the added iron performance standard. Iron values by the dry ash method were approximately double those of the wet ash method. The difference was a result of incomplete volatilization of the organic matrix by hydrochloric acid in the wet ash procedure. The performance standards developed from the wet and dry ash methods were 1.8 and 3.2 mg added iron 100 −1 g, respectively. Added iron levels from the dry ash method greater than 3.2 mg 100 −1 g were present in 60% of the AMR lean indicating that some marrow was present or that factors other than amount of iron in hand boned lean should be considered before a performance standard is established.

Classical wet ashing versus microwave-assisted attacks for the determination of chromium in plants

Microwave-assisted pre-treatments for the determination of Cr in plants are compared with classical wet-ashing procedures using open attacks in sand-baths. Four certified plant reference materials were analysed: pine needles (NIST SRM 1575), rye grass (BCR CRM 281), beech leaves (BCR CRM 100) and an aquatic plant (Trapa natans) (BCR CRM 596). The use of acidic procedures with HClO4 or H2SO4 yielded different Cr results for these materials when classical wet-ashing procedures were used, as the use of HClO4 caused losses of volatile chromium compounds. The shorter time of analysis required (60 min) in open-focused microwave-assisted attack allows the use of HClO4 for obtaining results very close to the certified values for CRM plant materials. This type of microwave digestion also led to good reproducibility values with relative standard deviations between 5 and 10%.

Microwave dissolution of plant tissue and the subsequent determination of trace lanthanide and actinide elements by inductively coupled plasma-mass spectrometry

Recently there has been much concern about the ability of plants to uptake heavy metals from their surroundings. With the development of instrumental techniques with low detection limits, such as inductively coupled plasma-mass spectrometry (ICP-MS), attention is shifting toward achieving faster and more elegant ways of oxidizing the organic material inherent in environmental samples. Closed-vessel microwave dissolution was compared with conventional methods for the determination of concentrations of cerium, samarium, europium, terbium, uranium, and thorium in a series of samples from the National Institute of Standards and Technology and from fields in Idaho. The ICP-MS technique exhibited detection limits in parts-per-trillion and linear calibration plots over three orders of magnitude for the elements under study. The results obtained by using nitric acid and hydrogen peroxide in a microwave digestion system for the analysis of reference materials showed close agreement with the accepted values. These values were compared with results obtained from dry- and wet-ashing procedures. The findings from an experiment comparing radiometric techniques for the determination of actinide elements to ICP-MS are reported.

Adaptation of a Dry Ashing Procedure for Determination of Selenium by Fluorimetry in High-Fat Foods

The wet ashing-dry ashing procedure for destruction of organic matter in high-fat foods for subsequent fluorimetric determination of selenium was investigated. Samples were decomposed by predigestion with nitric acid and dry-ashed with magnesium nitrate and hydrochloric acid. Selenium was recovered quantitatively through the total procedure. Detection limit was about 4 ppb. Accuracy was tested by analysis of several reference materials and by comparison with the wet-digestion method. The present method can be used conveniently for selenium determination in high-fat foods.

Methods of Analysis for Toxic Elements in Foods. Part IV. General Method of Ashing for the Determination of Toxic Elements

As a result of the request of the Codex Alimentarius Committee on Methods of Analysis and Sampling, a general method for ashing of foods for the determination of toxic elements was assembled. This method consolidates the results of more than a decade of interlaboratory work of numerous USSR food laboratories and specifies the details of wet and dry ashing procedures.