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PubMed1987

Trona and sodium bicarbonate in beef cattle diets: effects on site and extent of digestion.

Six yearling Hereford X Angus steers (avg 272 kg), each with ruminal, duodenal and ileal cannulas were used in a 6 X 6 Latin-square metabolism trial to evaluate the impact of NaHCO3 and trona (a ground, nonrefined ore with chemical composition NaHCO3-Na2CO3-2H2O) on site and extent of digestion of nutrients in the digestive tract. The diets were 50:50 or 90:10 (cracked corn-based concentrate:cottonseed hulls) with no buffer, 1% NaHCO3, or 1% trona. Intake, across all treatments, averaged 2.4% of body weight. Dry matter (DM) and starch digestibility (via indigestible acid detergent fiber) before the duodenum was decreased (P less than .10) with trona in the 50:50 diet. Digestibility of DM, crude protein and starch before the ileum were greater (P less than .05) in the 90:10 diet vs 50:50 diet. Total tract digestibility was similar across buffer treatments in the 90:10 diet. Addition of NaHCO3 increased (P less than .05) digestibility of dry matter and cell solubles in the 50:50 diet. Organic matter and crude protein digestibility were also increased (P less than .10) with NaHCO3. Apparent crude protein and cell solubles digestibility were greater (P less than .10) with trona than NaHCO3 in the 50:50 diet. This trial indicates that buffers provide overall enhancement of diet digestibility in mixed grain/roughage diets.

Animals↗
PubMed1988

Effect of predigestion factors on the apparent digestibility of protein for swine determined by the Mobile Nylon Bag Technique.

Five Yorkshire x Lacombe barrows (45 kg initial wt) fitted with duodenal cannulas approximately 10 cm from the pyloric sphincter were used to determine the influence of the pH of the predigestion solution (pH 1.0, 1.5, 2.0 or 2.5), pepsin activity (189 vs 377 IU/liter) and duration of predigestion (0, 1.5, 2.5 or 4.0 h) on the apparent digestibility of the protein in soybean meal (SBM), meal and bone meal (MBM) or canola meal (CM) determined with the Mobile Nylon Bag Technique (MNBT). An additional six barrows were used to determine protein digestibility by conventional methods. Protein digestibilities determined using conventional digestibility techniques were 93.1 +/- .7, 79.1 +/- 1.8 and 79.3 +/- 1.4% for the SBM, MBM and CM diets, respectively. Protein digestibilities determined with the MNBT were highest at pH 2.0 for all three protein sources. Increasing pepsin activity from 189 to 377 IU/liter resulted in a slight increase in the digestibility of SBM and CM, but not of MBM. The absence of predigestion (0 h) resulted in a dramatic reduction in protein digestibility; predigestion times of 1.5 or 2.5 h usually resulted in lower protein digestibilities than did a predigestion time of 4.0 h. The closest agreement between results obtained by the MNBT and conventional digestibility studies occurred with a pH of 2.0, a predigestion time of 4.0 h and a pepsin activity of 377 IU/liter.

Animals↗
PubMed2001

Effect of dental correction on feed digestibility in horses.

To test the hypothesis that routine dental correction (removal only of sharp hooks and points from molars and premolars) would improve digestion of a hay/grain ration whereas performance 'floats' (rounding and smoothing of the dental arcades) would adversely affect digestion, 8 mature horses free from dental correction for over a year were used. Five-day digestion trials were conducted before and 2 and 4 weeks after correction in all horses. Although all horses had sharp points and minor premolar hooks, none had severe dental abnormalities. There were no significant differences found in apparent digestion of dry matter, crude protein, neutral detergent fibre or acid detergent fibre relative to precorrection data or controls (uncorrected horses on same digestion trial). Apparent digestibility of crude protein and fibre, however, was reduced if the occlusal angle of premolar 307 was greater than 80 degrees relative to the vertical axis (flattened). It should be recommended that regular dental correction be continued. However, if only small points and hooks are present, correction will not significantly improve digestion. Performance floating does not adversely affect digestion 2-4 weeks after the procedure is performed. Alterations in molar occlusal surface angle may affect digestibility of protein and fibre.

Animal Feed↗
PubMed2002

Whole linted cottonseed as a forage substitute: fiber effectiveness and digestion kinetics.

Six ruminally and duodenally cannulated Holstein cows were used in a 6 x 6 Latin square design to 1) evaluate the potential interaction in effectiveness of neutral detergent fiber (NDF) from whole cottonseed (WCS) when it was substituted for forage NDF (FNDF) and fed with ground (G) or steam-flaked (SF) corn and 2) to determine whether the kinetic properties of NDF digestion further clarify the effectiveness of WCS. The six dietary treatments were: forage control with G corn (21% FNDF), 5% WCS with G or SF corn (18% FNDF), 10% WCS with G or SF corn (15% FNDF), and 15% WCS with G corn (12% FNDF). Based on chewing activity, the NDF from WCS was estimated to be 84% (SE = 36%) as effective as alfalfa silage NDF. Decreasing passage and digestion rates of potentially digestible NDF with increasing WCS increased the evacuated pool size of ruminal DM, apparently explaining the similar ruminal mat consistency among treatments. Measures of effectiveness ofWCS treatments did not interact with corn source. Fluid dilution rate was estimated based on a two-compartment model describing Co dilution, but no treatment differences were detected. There was a strong linear bias for estimates of ruminal NDF digestibility based on a single compartment model using the digestion rate of potentially digestible NDF and the passage rate of either indigestible NDF or digestible NDF when compared with NDF digestibility calculated using duodenal flows. Although further verification is needed, these digestion and passage kinetics help explain why WCS are effective at stimulating chewing during eating and rumination.

Animal Feed↗
PubMed1986

Digestibility of nitrogen in heat-damaged alfalfa.

In order to partition indigestible N in heat-damaged forages into its various chemical fractions, alfalfa (41.1% dry matter), stored in an upright stave silo, was not sealed, and heating was promoted. Silage was labeled as unheated silage (temperature below 20 degrees C); 35 degrees C silage (temperature near 35 degrees C, 5220 degrees C d); and 60 degrees C silage (temperature near 60 degrees C, 10,800 degrees C d). Total amino acid content of 60 degrees C silage was lower and acid detergent insoluble amino acid content was higher than in 35 degrees C or unheated silages. Apparent N digestibilities, determined using lactating dairy cows, were 47.5, 48.4, and 63.6% for 60 degrees C, 35 degrees C, and unheated silages. Estimates of true N digestibility were 76, 76, and 90%; true digestibility coefficients for amino acid N were 86, 92, and 95%; and true digestion coefficients for nonamino acid N were 67, 45, and 69% for 60 degrees C, 35 degrees C, and unheated silages. Two possible causes for depressed N digestibility of 60 degrees C silage were 1) the ratio of poorly digested nonamino acid N to highly digested amino acid N was higher in 60 degrees C silage than in 35 degrees C or unheated silage, and 2) amino acid N in 60 degrees C silage was digested less than amino acid N in 35 degrees C or unheated silage. Reasons for low digestibility of N in 35 degrees C silage are less clear, but evidence suggests formation of indigestible N complexes in digesta.

Animals↗
PubMed1989

Comparative digestion in sheep and cattle fed different forage to concentrate ratios at high and low intakes.

Effect of maintenance and ad libitum intakes on digestibility of different feed fractions was studied with six ruminally fistulated cows and six ruminally fistulated wethers to validate the use of sheep as a model for cattle. Complete diets were made up of ratios of alfalfa:cracked corn and soybean meal of 80:20, 55:45, and 30:70. The regression coefficient of the line relating organic matter digestibility with proportion of concentrate in the diet was smaller for the cows at ad libitum intake than for the other groups. Increasing the intake caused a decrease in digestibility of different fractions. The depression in digestibility was greater for the 30:70 forage:concentrate diet than for the others. At high intake, digestion values in the cows were less than those in the sheep for all diets. An increase in intake depressed the digestion of cell wall fractions and cell solubles including starch in cows, whereas in sheep, an increase in intake reduced cell wall digestion and to a lesser extent cell solubles, without affecting starch digestion. The digestive physiology of these species is sufficiently different to preclude the use of sheep data in formulating nutrient requirements for cows.

Animal Feed↗
PubMed1991

Feed intake and digestion by Holstein steers fed warm or cool season grass hays with corn, dried molasses, or wheat middlings.

This study determined the effects of adding a small amount of dried molasses to supplemental corn and of supplementing with corn, wheat middlings, or corn-wheat middlings mixture on intake and digestion by Holstein steers fed warn or cool season grass hays. Eight steers (175 kg BW), in two simultaneous Latin squares, were fed, once daily, bermuda-grass (72% NDF) or ryegrass-wheat (58% NDF) hay ad libitum, alone or with approximately .05% BW of dried molasses (with 31% roughage), 5% BW of ground corn, or both. Adding dried molasses to corn decreased feed intake but did not affect digestible OM intake. Total tract digestion of fiber from bermudagrass tended to be enhanced by adding dried molasses to corn. Eight steers (193 kg BW) were used in an experiment with the same design in which similar forages were fed alone or with corn (.5% BW), wheat middlings (.63% BW), or .25% BW of corn plus .31% BW of middlings. Feed intake for both grasses was similar among supplements. Wheat middlings depressed total tract fiber digestion more than corn with both forages. Supplementation with corn depressed fiber digestion slightly more with ryegrass-wheat than with bermudagrass, but wheat middlings had a slightly greater depressing effect on fiber digestion with bermudagrass. Associative effects of mixing corn and wheat middlings in OM digestion and digestible OM intake were negative for bermudagrass and positive for ryegrass-wheat. Interaction among characteristics of basal forage and concentrate modulated feed intake and digestion by ruminants.

Animal Feed↗
PubMed1997

Correlation of acid detergent lignin and Klason lignin with digestibility of forage dry matter and neutral detergent fiber.

The acid detergent lignin and Klason lignin methods were compared for their correlation with forage digestibility. Thirty-six forages, including C3 legumes and C3 and C4 grasses, were analyzed for sulfuric acid detergent lignin, Klason lignin, and in vitro digestibilities of dry matter (DM) and neutral detergent fiber (NDF). Twenty of these forages were also fed to lambs at restricted intake for measurement of DM and NDF digestibilities. Lignin concentrations determined by the two lignin methods were positively correlated, and the Klason lignin value was always greater than the acid detergent lignin concentration. The largest differences were observed for grass forages. Digestibilities of forage DM and NDF were negatively correlated with both lignin methods for the in vitro system and the lamb digestibility trials. The degree of correlation for the two lignin methods with digestibility was generally similar across all forages and within forage classes. Slopes of linear regressions of digestibility on lignin concentration did not differ between legumes and grasses. Although the sulfuric acid detergent lignin and Klason lignin procedures gave very different estimates of forage lignin concentration, they were similarly correlated with digestibility and should yield predictions of forage digestibility that have similar accuracy.

Animal Feed↗
PubMed2001

Disproportion of economic impact, research achievements and research support in digestive diseases in Canada.

OBJECTIVES: To assess the economic impact, research output and research support of digestive diseases, and to compare them to those of other common disease entities, specifically mental, cardiovascular, respiratory, and central nervous system diseases. METHODS: Economic burden was assessed with the use of (a) published Canadian government data of direct cost from 1963 to 1993, (b) data from the Canadian Institute of Health Information and (c) recent Canadian economic studies. Research achievements were assessed on the basis of (a) research training in Canadian units, (b) individual achievements by Canadian investigators and (c) contribution to meetings and reception of awards. Research support was assessed by reviewing (a) Canadian government publications, (b) the Association of Canadian Medical Colleges, (c) the Medical Research Council (MRC) of Canada, (d) charitable organizations and (e) the Canadian Association of Gastroenterology (CAG). RESULTS: Digestive diseases are responsible for 15% of the total direct economic burden of Canadian health costs, and this figure exceeds those for mental, cardiovascular, respiratory and central nervous system diseases. Hospital discharges for digestive diseases contribute 12% of all hospitalizations and 20% of all neoplasias. Digestive diseases cause short-term loss of productivity, costing $1.14 billion/yr and exceeding the costs of mental, cardiovascular, respiratory and central nervous system diseases. Eighty-one percent of Research Fellows trained in Canadian units entered academic positions, and 63% obtained operating grants. Canadian investigators made important contributions in all areas of digestive science and received major international awards. Government support for digestive diseases was less than that for cardiovascular and neurologic research. In contrast to the highest economic burden, university staffing and residents were fewer for digestive than for mental, cardiovascular, respiratory and neurologic diseases. The number of MRC grants decreased, mainly because of organizational problems. Most charitable organizations support research specifically oriented to the disease of their interest. The CAG was the major supporter of non-specified research. CONCLUSIONS: Digestive diseases are responsible for a major economic burden. Scientists in this field have established international recognition, but research support lags behind the need to correct the economic burden and to provide future generations of scientists in the digestive sciences. There is need for government to readdress this shortcoming and to review its method of support.

Canada↗
PubMed1979

[The digestibility in vitro of some lignocellulose materials].

In our experiments we tested 11 kinds of different lignocellulose materials by means of the method in vitro according to Mellenberger et al. (1970) for a determination of their digestiblity. In experiments carried out with beech sawdust treated with 0.1 M of sulphuric acid a digestibility of 3.7% was found, in sawdust treated with 0.47 M of nitric acid a digestibility of 61.6% was found and after a neutralization with ammonia it amounted to 72.2%. Wood fibre (WF-1) treated enzymatically showed a digestibility of 28.6% and in the WF-2 complemented with newsprint paper it amounted to 33.4%. Untreated beech waste -- forest billets -- showed a low digestibility (5.6%) and that of zero fibre was somewhat higher (12.6%). Difibered beech sawdust showed a digestibility of 44.0% and the digestibility of the biomass prepared from lye waste obtained during the production of cellulose fibres amounted to 74.1%. Waste fibre also showed a high digestibility of 76.0%. Straw enriched with yeast proteins (SL-1) showed a digestibility of 58.0%. Cellulose used as a standard in the course of the testing of lignocellulose materials showed the highest digestibility -- 82.3%.

Cellulose↗
PubMedDate not supplied

Degradation of peptide drugs by immobilized digestive proteases.

An in vitro assay using immobilized digestive enzymes and LC/MS has been developed to measure the susceptibility of orally administered peptide drugs to hydrolysis by the digestive system. Six different bioactive peptides and peptide drugs were digested using an established in vitro system incorporating four sets of immobilized digestive enzymes, which simulated gastric digestion in the stomach, digestion by pancreatic enzymes in the intestinal lumen, and digestion by mucosal peptidases at the intestinal brush border. Hydrolysis products were rapidly identified using LC/MS and coincided with those expected based on the substrate specificities of the immobilized enzymes. The LC/MS system consisted of a reversed phase HPLC connected to a mass spectrometer through a continuous-flow fast atom bombardment ionization system. Data acquired on the susceptibility of peptide drugs to hydrolysis by digestive enzymes could be used during the formulation of orally administered drugs to protect them from degradation prior to absorption in the gut. Also, this assay could be used to quickly identify those compounds in a structurally related series of new drugs that are most resistant to digestive proteases.

Amino Acid Sequence↗
PubMed1984

Protein digestibility of methionine supplemented common beans (Phaseolus vulgaris) in adult human subjects.

The study reports on the protein digestibility of five cultivars of common beans (Phaseolus vulgaris) of different color, tested in young adult human subjects, as the sole dietary protein source. Cheese protein was used as reference protein. The cooked beans provided 0.65 g protein/kg/day, and energy intake was adjusted to 45 kcal/kg/day. Results indicated apparent protein digestibility to vary from 49.6 to 62.1%. White colored beans showed the highest value, while black beans gave the lowest. Cheese protein showed an apparent protein digestibility of 76.2%. The true protein digestibility was calculated using the endogenous nitrogen excretion values obtained in the study, as well as literature values. Digestibility increased as expected, but it is still low as compared to other protein sources. A high correlation was found between dry matter digestibility and protein digestibility. Fecal nitrogen was fractionated between soluble and insoluble nitrogen in a 0.02 N NaOH solution. This assay was also carried out in the cooked beans, and findings revealed that the soluble nitrogen fraction was highly correlated with protein digestibility, with a correlation coefficient of -0.94. This fraction, still to be identified, could very well be responsible for the low digestibility values found for common beans in human subjects.

Adult↗
PubMed1997

Phylogenetic analysis of the evolution of lactose digestion in adults.

In most of the world's population the ability to digest lactose declines sharply after infancy. High lactose digestion capacity in adults is common only in populations of European and circum-Mediterranean origin and is thought to be an evolutionary adaptation to millennia of drinking milk from domestic livestock. Milk can also be consumed in a processed form, such as cheese or soured milk, which has a reduced lactose content. Two other selective pressures for drinking fresh milk with a high lactose content have been proposed: promotion of calcium uptake in high-latitude populations prone to vitamin-D deficiency and maintainance of water and electrolytes in the body in highly and environments. These three hypotheses are all supported by the geographic distribution of high lactose digestion capacity in adults. However, the relationships between environmental variables and adult lactose digestion capacity are highly confounded by the shared ancestry of many populations whose lactose digestion capacity has been tested. The three hypotheses for the evolution of high adult lactose digestion capacity are tested here using a comparative method of analysis that takes the problem of phylogenetic confounding into account. This analysis supports the hypothesis that high adult lactose digestion capacity is an adaptation to dairying but does not support the hypotheses that lactose digestion capacity is additionally selected for either at high latitudes or in highly arid environments. Furthermore, methods using maximum likelihood are used to show that the evolution of milking preceded the evolution of high lactose digestion.

Adult↗
PubMed1992

Histochemical changes in the midgut of two ixodid tick species Boophilus microplus and Rhipicephalus appendiculatus during digestion of the blood meal.

The changes in the midgut epithelia of two ixodid tick species, Boophilus microplus and Rhipicephalus appendiculatus, have been studied using several histochemical techniques. It was revealed that there is an accumulation of RNA at the time of tick attachment to the host and prior to the arrival of the blood meal, indicating that the midgut digest cell is furnished with the machinery characteristic of a synthetic cell. There appears to be a synchrony in the appearance of granules with peroxidase activity and the uptake of haemoglobin into the midgut digest cells. Alkaline phosphatase activity was observed in the midgut epithelia of all ticks except in a few of the long-starved ticks, and was concentrated in the apical plasma membrane regions of those digest cells involved in absorption and the intracellular digestion of haemoglobin. The presence of these enzymes suggests that the midgut digest cell is a multifunctional cell capable of both secretory and digestive activities. The colloidal material in the midgut lumen was found to result from the accretion of several products both secreted and excreted by the midgut epithelial cells and exhibited different staining reactions depending on which component dominated. The nature of the material suggests that in addition to its its digestive function it may serve as a sink to bind all the by-products of digestion and thereby facilitate their excretion.

Alkaline Phosphatase↗
PubMed2007

Evaluation of thermophilic anaerobic digestion processes for full-scale Class A biosolids disinfection at Hyperion Treatment Plant.

This paper describes 5 phases of full-scale testing at the City of Los Angeles Hyperion Treatment Plant (HTP) for producing Class A biosolids (U.S. EPA Part 503 Biosolids Rule) by thermophilic anaerobic digestion. Phases I and II were tests with a two-stage continuous-batch process in a thermophilic battery of six digesters and a designated post-digestion train that was isolated from mesophilic operations. These tests demonstrated that digester outflow biosolids met the Class A limits for fecal coliforms and Salmonella sp. However, fecal coliform densities sharply increased during post-digestion. The recurrence was possibly related to a combination of a large drop of the biosolids temperature after the dewatering centrifuges and contamination of thermophilically digested biosolids from mesophilic operations. Phase III was conducted after insulation and electrical heat-tracing of the post-digestion train to maintain a biosolids temperature throughout post-digestion at about the same level as in the digester outflow. Biosolids monitoring at the last points of plant control (silos at Truck Loading Facility and farm for land application) indicated that fecal coliform recurrence was prevented. After completing the conversion of HTP to thermophilic operation, certification tests of Phases IV and V demonstrated Class A compliance of a two-stage continuous-batch process under Alternatives 1 and 3 of the Part 503 Biosolids Rule, respectively. HTP received the permit for Class A (indeed exceptional quality) biosolids land application in Kern County, California, in December 2002 under Alternative 3. Since 2003, HTP has consistently complied with the federal and local standards for Class A biosolids, indicating that Class A limits can be met under conditions less stringent than defined by the Alternative 1 time-temperature requirement for batch treatment.

Bacteria, Anaerobic↗
PubMed1995

DNA probe assay based on exonuclease III digestion of probes hybridized on target DNA.

A quantitative DNA probe assay process has been developed that uses exonuclease III. The fluorophore-labeled DNA probe is hybridized with specific sequences of the target DNA and then enzymatically digested. As these probe hybridization and digestion cycle reactions are repeated at a fixed temperature, digested probes (shortened probes) accumulate in the reaction mixture in a manner similar to a DNA polymerase chain reaction. Investigation of the digestion characteristics of the DNA probe showed that a slight digestion of a free single-stranded probe produces a large background signal, which results in low detection sensitivity. The digestion of single-stranded DNA probes is caused by double-stranded formations in the molecules. This digestion decreases and the double-stranded-specific digestion increases with increasing reaction temperature. When the reaction occurs at 45 degrees C, the association rate of the enzyme on the double-stranded DNA is 700 times faster than that on single-stranded DNA. This enables selective digestion of double-stranded DNA. The detection limit is 9 x 10(-19) mol for a M13-phage DNA.

Animals↗
PubMed1989

Histochemical demonstration of O-glycosidically linked, type 3 based ABH antigens in human pancreas using lectin staining and glycosidase digestion procedures.

Histochemical analyses of the chemical structures of sugar sequences with or without blood group specificity were carried out by combined stepwise digestion of tissue sections with exo- and endoglycosidases and subsequent lectin stainings in formalin-fixed, paraffin-embedded human pancreas. In acinar cells from blood group A or AB secretor individuals, sequential digestion with alpha-N-acetylgalactosaminidase and alpha-L-fucosidase imparted reactivity with peanut agglutinin (PNA) in cells reactive with Dolichos biflorus agglutinin as well as those with Ulex europaeus agglutinin I(UEA-I). Simple fucosidase digestion imparted the PNA reactivity only in UEA-I reactive cells. Sequential digestion with alpha-galactosidase and fucosidase likewise liberated the PNA binding sites in Griffonia simplicifolia agglutinin I-B4 reactive cells from blood group B and AB secretors. Sialidase digestion liberated the PNA binding sites not only in acinar cells but also intercalated duct cells, islet cells of Langerhans and endothelial cells. The PNA reactivity obtained by these enzyme digestions was eliminted by endo-alpha-N-acetylgalactosaminidase (endo-GalNAcdase) digestion. Preexisting PNA affinity in acinar cells from non-secretors was also susceptible to endo-GalNAcdase treatment. Following the endo-GalNAcdase digestion, fucosidase or sialidase digestion recovered the PNA reactivity in acinar cells from nonsecretors. These results show that ABH determinants carried on O-glycosidically linked type 3 chain (D-galactose-(beta 1-3)-N-acetyl-D-galactosamine alpha 1-serine or threonine) are secreted in pancreatic acinar cells and suggest that product coded by the secretor gene is required for the complete conversion of type 3 precursor chains into H determinants.

ABO Blood-Group System↗
PubMed2003

Measurements of sulfur in oil using a pressurised wet digestion technique in open vessels and isotope dilution mass spectrometry.

Graz University of Technology has developed a new technique for digesting samples using the well-established high-pressure asher (HPA) from Anton Paar GmbH (Graz, Austria). The digestion is performed in semi-open vessels inside a pressurised autoclave. The new HPA equipment consists of a liner for the autoclave, special sample racks and 30-mL digestion vessels made of quartz, covered with PTFE stoppers. The Laboratory for Isotope Dilution and Nuclear Analysis of the Federal Institute for Materials Research and Testing (BAM, Berlin) tested this new equipment in order to assess its usability for the decomposition of larger sample amounts of gas oils for the measurement of sulfur. Several experiments were carried out using the new sample decomposition technique. In order to test the recovery of the new digestion method, a gas oil material with known sulfur content was chosen, quantified by the validated conventional closed vessel HPA digestion in combination with thermal ionisation mass spectrometry. Isotope dilution mass spectrometry has been applied as analytical method in this investigation. The gas oil was spiked with an isotopic spike material, which is enriched in (34)S, and was then wet digested in the HPA. The oxidized sulfur of the dried samples was reduced to H(2)S and precipitated as As(2)S(3). The sulfur was measured as arsenic monosulfide (AsS(+)). The mass content of sulfur in the gas oil tested is 453.5 mg kg(-1). Recovery tests for increasing masses of gas oils indicate that the recovery using the new measurement technique decreases with increasing mass of gas oil. Results were obtained for approximately 0.3 g sample weight and had less overlap with the result of the old HPA method within the stated uncertainties. At approximately 0.5 g sample weight the yield decreases to about 97% and at approximately 1.0 g sample weight to about 87%. In comparison with the conventional closed vessel HPA digestion, the new technique shows no clear advantages for the certification of the sulfur content in gas oil other than a more convenient handling. The total uncertainty of the sulfur mass fractions (k=2) is about 1.5%. Repeated determination of the oil samples show a relative standard deviation of about 0.8% and indicate that the analytical procedure is robust and reproducible. The demonstrated reproducibility allows the establishment of correction factors for the yield, which in turn enables higher sample masses for routine work. The blank level (0.26 x 10(-6) g) was within the range of the conventional closed HPA digestion procedure.(0.28 x 10(-6) g). Cross contamination could not be detected. In terms of trace metal analysis a good applicability and more advantages over the conventional closed vessel HPA digestion can be assumed.

Journal Article↗