More Powerful Peroxide Kjeldahl Digestion Method

Hach, Clifford C.; Bowden, Brian K; Kopelove, Alan B.; Brayton, Scott V.

doi:10.1093/jaoac/70.5.783

Cited by 123 publications

(91 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This means Barbarino and Lourenço CHN versus Hach that studies that involve determinations of total nitrogen of marine organisms could be performed using any of the methods. This validates the method of Hach et al (1987), a methodological alternative that holds lower analytical costs compared to elemental composition CHN, especially in countries where labor costs are low. The use of Hach's procedures brings the advantage of allowing the use of the same digested samples for other analyses, such as total phosphorus (see Lourenço et al 2005Lourenço et al , 2006.…”

Section: Discussionsupporting

confidence: 69%

“…Total nitrogen was also determined in the same samples analyzed for CHN elemental composition by peroxymonosulfuric acid digestion, using a Hach digestor (Digesdhal ® , Hach Co., model 23.130-20) (Hach et al 1987). Freeze-dried samples containing 50-120 mg were put into the special digestion flask and digested with 4.0 mL concentrated (95% to 98%) sulfuric acid (Merck) at 440°C, for 3 min (or until visible destruction of the material).…”

Section: Materials and Proceduresmentioning

confidence: 99%

“…In the 1980s, Hach et al (1985Hach et al ( , 1987) created a new methodological alternative to determine total nitrogen. The method involves a hot acid digestion of samples with sulfuric acid for a few minutes, followed by oxidization with hydrogen peroxide.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comparison of CHN analysis and Hach acid digestion to quantify total nitrogen in marine organisms

Barbarino

Lourenço

2009

Limnology & Ocean Methods

View full text Add to dashboard Cite

The quantification of total nitrogen in biological samples has wide applications in marine sciences. Different methods are currently used to quantify nitrogen content, but their accuracies have not been extensively tested with samples of marine origin. In this study, we compared results for total nitrogen analysis generated by the Hach method, a relatively new and low-cost technique, with CHN elemental analysis, a widely accepted and costly technique. Sixty aquatic organisms were tested covering substantial biological diversity, including algae, invertebrates, fishes, mangrove plants, salt marsh plants, and seagrasses. Two pure protein standards (bovine serum albumin and bovine milk casein) were also tested. All materials were tested using freeze-dried samples. Fishes showed the highest concentrations of nitrogen, with values always higher than 14%, whereas leaves of mangrove plants showed the poorest N content among all species (<2.0%). In general, animals showed higher values for total nitrogen than algae and spermatophytes. Results obtained with CHN analysis and the Hach method were compared for each species based on triplicate analyses for each method. Comparisons for each species showed no statistical differences between the techniques, which yielded virtually identical nitrogen measurements. In addition, results obtained with both CHN analysis and the Hach method for the two pure protein standards were similar to data provided by the manufacturer. The set of results indicates that the Hach method is suitable for nitrogen analysis of marine organisms and should be considered as an inexpensive and accurate alternative for nitrogen quantification.

show abstract

Section: Discussionsupporting

confidence: 69%

Section: Materials and Proceduresmentioning

confidence: 99%

See 1 more Smart Citation

Comparison of CHN analysis and Hach acid digestion to quantify total nitrogen in marine organisms

Barbarino

Lourenço

2009

Limnology & Ocean Methods

View full text Add to dashboard Cite

show abstract

“…Kjeldahl's method (AOAC 1990) is widely used to quantify nitrogen content, because it is inexpensive and technically easy. This technique has been modified, making it faster and less hazardous (Hach et al 1987), but equally accurate (Watkins et al 1987).…”

mentioning

confidence: 99%

Distribution of Intracellular Nitrogen in Marine Microalgae: Basis for the Calculation of Specific Nitrogen‐to‐protein Conversion Factors

Lourenço

Barbarino

Marquez

et al. 1998

Journal of Phycology

156

View full text Add to dashboard Cite

The utilization of nitrogen‐to‐protein conversion factors (N‐Prot factors) is a widely accepted and practical way to determine total protein content. The accuracy of protein determination depends on the establishment of specific N‐Prot factors, since the conventional factor of 6.25 may be unsuitable for all species. This study was designed to determine the concentrations of the main nitrogenous compounds and to establish N‐Prot factors specific for the following marine microalgae: Chlorella minutissima, Dunaliella tertiolecta, Hillea sp., Isochrysis galbana, Nannochloropsis oculata, Phaeodactylum tricornutum, Prorocentrum minimum, Skeletonema costatum, Synechococcus subsalsus, and Tetraselmis gracilis. Cultures were maintained under a 12‐h photoperiod (300 μmol photons·m−2·s−1) at temperatures of 20.0°± 1.0° C (dark) to 23.0°± 2.0° C (light) in Walne’s culture medium without additional external carbon sources. The distribution of intracellular nitrogen was studied by determining total nitrogen (TN, by CHN [carbon, hydrogen, and nitrogen] analysis), protein N (PN, by analysis of total amino acids), and nonprotein N (NPN, determined by analysis of DNA, RNA, chlorophylls (chl) a,b, and c, and intracellular inorganic nitrogen—NO3−, NO2−, and NH3+ NH4+) in logarithmic and stationary growth phases of cultures. Variations occurred in both accumulation and distribution of PN and NPN among the species, as well as in each species during the different growth phases. Inorganic nitrogen compounds were observed to be the most important NPN source (from 6.4 ± 0.1% to 41.8 ± 4.2% of total N) in all species (except D. tertiolecta), followed by nucleic acids (from 0.8 ± 0.1% to 26.1 ± 2.4% of TN) and chlorophylls (from 0.2 ± 0.0% to 3.1 ± 0.3% of TN). Total amino acid residues ranged from 63.1 ± 4.6% up to 88.1 ± 11.2% of TN, which is in agreement with the presence of high NPN concentrations. N‐Prot factors are proposed for each growth phase in the studied species, based on the ratio of amino acid residues to TN, establishing specific N‐prot factors ranging from 3.60 ± 0.27 to 4.99 ± 0.64. The mean N‐Prot factor for all species/growth phases was 4.58 ± 0.11. The present study shows that the use of the traditional factor 6.25 is not suitable for these marine microalgae, and possibly for other species, because it overestimates their actual protein content.

show abstract

“…The samples were oven-dried (for 5 days at 60°C), ground, and stored at room temperature. Kjeldahl digestion was used to determine nitrogen content (Hach et al, 1987).…”

Section: Some Leaves Of the Plants Used For Life Table Experimentsmentioning

confidence: 99%

Bottom‐up effect of host plants on life‐history characteristics of Aphidoletes aphidimyza feeding on Aphis gossypii

Madahi

Sahragard

Hosseini

et al. 2019

Entomologia Exp Applicata

View full text Add to dashboard Cite

The predatory midge Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae) is widely used for the control of Aphis spp. in many agricultural systems. We aimed to determine the most suitable host plant for rearing the predatory midges on the prey Aphis gossypii Glover (Hemiptera: Aphididae). Six host plants were selected: cucumber (Cucumis sativus L. cv. Beith Alpha), tomato (Solanum lycopersicum L. cv. Falat111), eggplant (Solanum melongena L. cv. Yummy), pepper (Capsicum annuum L. cv. Bertene) (all Solanaceae), okra [Abelmoschus esculentus (L.) Moensch cv. Clemson Spineless] (Malvaceae), and squash (Cucurbita pepo L. cv. Hybrid rajai) (Cucurbitaceae). Some physical traits (length and density of trichomes) and chemical attributes (nitrogen content) of prey host plants were investigated. The results showed that prey host plants differed significantly in their effect on fitness of the predator. The shortest immature development time (18.07 ± 0.257 days), the longest female adult longevity (7.5 ± 0.18 days), and the highest fecundity (89 eggs/female) of A. aphidimyza were found with squash as prey food. The highest intrinsic rate of increase (0.171 ± 0.009 day−1) and also the shortest mean generation time (22.4 ± 0.32 days) were also obtained when A. aphidimyza fed on A. gossypii reared on squash. Canonical correlation analysis (CCA) approved the correlation between life‐history traits of A. aphidimyza and characteristics of prey host plants. The suitability of squash for rearing A. aphidimyza can be attributed to the higher nitrogen content, longer trichomes, and relatively high density of trichomes, which provided a better environment for A. gossypii and indirectly favored A. aphidimyza. This study showed that squash is the most suitable host plant for rearing A. aphidimyza feeding on A. gossypii.

show abstract

More Powerful Peroxide Kjeldahl Digestion Method

Cited by 123 publications

References 0 publications

Comparison of CHN analysis and Hach acid digestion to quantify total nitrogen in marine organisms

Comparison of CHN analysis and Hach acid digestion to quantify total nitrogen in marine organisms

Distribution of Intracellular Nitrogen in Marine Microalgae: Basis for the Calculation of Specific Nitrogen‐to‐protein Conversion Factors

Bottom‐up effect of host plants on life‐history characteristics of Aphidoletes aphidimyza feeding on Aphis gossypii

Contact Info

Product

Resources

About