HCl Extraction Research Articles

Optimization and validation of direct gas chromatography-mass spectrometry method for simultaneous quantification of ten short-chain fatty acids in rat feces

Short-chain fatty acids (SCFAs) play key roles in maintaining health and treating disease. Quantification of important fecal SCFAs is necessary to facilitate the clarification of their biological roles. However, the existing quantifying methods mainly depend on complicated precolumn derivatization, and/or are unable to determine formic acid, a SCFA commonly associated with toxicity. In this study, a direct gas chromatography-mass spectrometry (GC-MS) method for simultaneous quantification of ten SCFAs including formic acid in rat feces was developed. The approach was optimized in terms of chromatographic and spectrometric conditions as well as sample preparation. DB-FFAP capillary column with temperature programming was used to get baseline separation and symmetrical peak shape of SCFAs without precolumn derivatization in a relatively short running time (8 min). Multiple reaction monitoring (MRM) scan mode was employed to enhance the sensitivity and selectivity of SCFAs. Acidification with 50% HCl and immediate extraction with diethyl ether were utilized to achieve sample preparation of ten SCFAs from feces. Furthermore, the developed method was validated with wide linear range, high sensitivity and precision, low matrix effect and acceptable accuracy. The established method was successfully applied to compare the contents of fecal SCFAs between normal and immunosuppressed animal models.

Distribution of Pb isotopes in different chemical fractions in bed sediments from lower reaches of the Xiangjiang River, Hunan province of China

This paper reports Pb isotopes in different fractions following the three step BCR and 1 M HCl extractions on river sediments from lower reaches of the Xiangjiang river in China, and highlights the importance of Pb isotopes in heavy metal contamination assessment. Lead concentrations and Pb isotopes in bulk sediments and sediment fractions (leachates and residues) from the river were analysed using ICP-MS techniques. Results showed that sediments were highly enriched with Pb with enrichment factors >5.5, while Pb in sediments was dominated by reducible and residual Pb fractions, residing mainly in Fe-oxide and silicate minerals. Pb isotopes in sediments was characterized by radiogenic Pb produced from the decay of uranium and thorium with 206Pb/207Pb ratios of 1.1744 for less radiogenic Pb and 1.1816 for more radiogenic Pb. The leachates and residues from BCR extraction generally had similar Pb isotope compositions, of which the 206Pb/207Pb ratios were 1.1798 ± 0.002 and 1.1844 ± 0.008 respectively. Differentiation of Pb isotopes between BCR leachates and residues was insignificant. However, differentiation between leachates and residues using 1 M HCl extraction was significant, as shown by average 206Pb/207Pb ratios of 1.1746 ± 0.005 and 1.1858 ± 0.008 for leachates and residues respectively. Pb isotopic tracing suggests that Pb in sediments from Zhuzhou section arose from the mixing of anthropogenic Pb from coal combustion (39%) and mining-smelting for Pb-Zn ores (58%); while Pb in sediments from Xiangtan, Changsha and Xiangyin sections arose from the mixing of anthropogenic Pb from mining-smelting for Pb-Zn ores (54%), and lithologically inherited Pb from granite weathering (35%) with a small amount of contribution from coal combustion (10%). The present study suggests that the BCR extraction scheme was not appropriate for ecological risk assessment of heavy metal contamination in mining-impacted (ore-Pb dominated) river sediments.

Synthesis and characterization of geopolymer prepared from circulating fluidized bed-derived fly ash

The use of circulating fluidized bed fly ash (CFBFA) to prepare geopolymer as a substitute for cement not only reduces CO2 emissions, but also solves many environmental problems caused by the large amount of CFBFA stockpiles. The effects of alkali activator modulus (SiO2/Na2O molar ratio) and curing temperature on the mechanical properties of geopolymers were investigated, and the intrinsic relationship between mechanical properties and phase composition, micromorphology and chemical structure was established by XRD, SEM, FTIR, and NMR characterization, and the HCl extraction experiments were used to investigate geopolymerization mechanism. The results show that the compressive strength of geopolymer decreases as the alkali activator modulus increases from 1.0 to 1.8. The compressive strength of geopolymer within 7 days can be increased greatly when the curing temperature increased from ambient temperature to 60 °C, but it decreased significantly after 28 days. The 90 days compressive strength reaches 34.7 MPa under the curing temperature of 20 °C and the activator modulus of 1.0. Combined with the results of XRD, FTIR, and SEM, it was known that when the curing temperature reaches 60 °C, the geopolymer gels were transformed into the zeolite-like phase in the later stages of curing, leading to reduce in compressive strength, whereas ambient temperature curing was conducive to the growth of gels. NMR results show that the Q4(2Al)+Q4(1Al) structure was mainly dominated in the geopolymer in the early stage of curing under ambient temperature, and the Q4(4Al)+Q4(3Al) structure gradually increased when the curing exceeded 28 days. When the curing temperature was 60 °C, the structure gradually transformed to a single Q4(2Al) structure as the curing age increases.

Mathematical Model of FeCl3 and HCl Extraction in the FeCl3–HCl–H2O–Undecan-1-ol System

Mathematical Model of FeCl3 and HCl Extraction in the FeCl3–HCl–H2O–Undecan-1-ol System

Improving the shelf life of chicken burgers using Octopus vulgaris and Dosidicus gigas skin pigment extracts

In this work, an innovative strategy for raw chicken burger preservation, based on methanol–HCl extracts of octopus (Octopus vulgaris) (OVE) and squid (Dosidicus gigas) (DGE) skin pigments, was evaluated at 4 °C for 12 days. Burgers were prepared and divided into six groups: the control without any extract (CON), the control with 0.03% α-tocopherol (CET), and those containing 0.05% (OVE1, DGE1) and 0.1% (OVE2, DGE2) octopus and squid pigment extract, respectively. OVE yielded a higher rate of pigments with antioxidant activity (DPPH, ABTS, and ORAC) than DGE. The highest antimutagenic activity was detected in DGE according to the Ames’ Salmonella test. OVE1 and DGE1 burgers maintained lower pH values and were less sensitive to lipid oxidation (peroxide, anisidine, and total oxidation values). Evaluation of microbial growth by total bacterial count, lactic acid bacteria, Enterobacteriaceae spp., and fungi showed that OVE1 and DGE1 delayed bacterial contamination. The overall sensory quality was maintained for longer in the OVE- and DGE-supplemented chicken burgers than CON burgers. This study showed that OVE and DGE have potential as antioxidant and antimicrobial additives in chicken products.

DECOMPOSER ACTIVITIES OF EUDRILUS EUGENIAE, EISENIA FETIDA, AND LUMBRICUS RUBELLUS: QUALITY OF MUSHROOM WASTE SUBSTRATE VERMICOMPOST

This study aimed to analyze the vermicompost quality of mushroom substrate waste (without other substrates) produced by Lumbricus rubellus, Eisenia fetida, and Eudrilus eugeniae worms. The chemical quality of vermicompost was analyzed using the Kjeldahl and 25% HCl extraction and measured by spectrophotometer and flame photometer. Meanwhile, the biological quality was analyzed using the Total Plate Count, Nelson-Somogyi, and Most Probability Number (MPN) methods. Vermicompost's chemical and biological quality was compared with the compost quality standards in Indonesia and abroad. The results showed that the levels of N+P2O5+K2O, micronutrients (Fe, Mn, Zn), and heavy metals (Pb and Cd) in vermicompost were 5.9%, 0.95-27.5 ppm, and < 0.25 ppm, respectively. The levels of N+P2O5+K2O are by the quality standards of compost in Indonesia, Tanzania, the Philippines, and Thailand; the micronutrients (Fe, Mn, Zn) are by the means in Indonesia. The heavy metals (Pb and Cd) levels meet the applicable standards in Indonesia, England, Belgium, Germany, Italy, Canada, and the USA. The contents of E. coli, N-fixing microbes, and phosphate solubilizing microbes (PSM) in vermicompost were < 26.5 MPN g-1, 1.00' 105 - 31.00' 105 cfu g-1, and 0.40' 105 - 39.00' 105 cfu g-1, following the applicable standards in Indonesia and Europe (E. coli with a maximum of 1000 MPN g-1 and the number of N-fixing microbes and PSM of at least 1.00' 105 cfu g-1).

Allosteric extraction of a second gallium anion assisted by the first, loaded onto a fluorinated secondary amide reagent

• Two secondary amide compounds with and without fluorine atoms were synthesised. • Both extractants exhibited high Ga(III) selectivity in hydrochloric acid media. • The stoichiometries for both extractants to Ga(III) were determined. • The N-H hydrogen atom contributed to Ga(III) extraction at low HCl concentrations. • Allosteric extraction assisted by hydronium was observed for fluorinated reagent. Two secondary amide compounds with and without fluorine atoms, N -(2-ethylhexyl)-2,2,2-trifluoroacetamide (TFAA) and N -(2-ethylhexyl)acetamide (AA), respectively, were synthesised in high yield under different reaction conditions. Both extraction reagents exhibited selectivity for Ga(III) over other metals in competitive solutions from hydrochloric acid media. Comparatively, the extraction selectivity of TFAA was superior to that of AA because of the electron-withdrawing nature of fluorine atoms, which increased the charge density on the N-H hydrogen atom and decreased electron density on the carbonyl oxygen atom of TFAA. The stoichiometries for both extraction reagents to Ga(III) were determined by slope analysis for concentrations of extractants, protons, and chloride ions. FT-IR, 1 H NMR, and 19 F NMR spectroscopic analyses were conducted to elucidate the extraction mechanism. At high HCl concentrations, AA was protonated; consequently, GaCl 4 – was extracted with assistance from the O-bound hydronium ion, while at low HCl concentrations, AA was not protonated and GaCl 4 – and a hydronium ion as a counter cation were extracted via the N-H hydrogen atom. On the contrary, TFAA was not protonated over the entire tested HCl concentration range and extraction of GaCl 4 – occurred only via the N-H hydrogen atom and a hydronium ion as a counter cation. One proton of the hydronium ion bonded to GaCl 4 – and one to an electron-withdrawing fluorine atom; consequently, the remaining hydrogen atom is partially positively charged and extracts a second GaCl 4 – accompanied by a second hydronium ion. Overall, the mechanism involves an allosteric extraction of a second GaCl 4 – assisted by an already TFAA-bound Ga(III) and hydronium ion. Exhaustive stripping of Ga(III) from the organic phase after forward extraction with either amide can be achieved using distilled water.

Performance of different extraction methods for paralytic shellfish toxins and toxin stability in shellfish during storage.

Accurate analysis of paralytic shellfish toxins (PSTs) in shellfish is important to protect seafood safety and human health. In this study, the performance of different extraction protocols for PSTs from scallop tissues is compared and discussed, including regular extraction solvents hydrochloric acid (HCl) and acetic acid (AcOH) followed by heating and solid-phase extraction (SPE) purification, and a novel technique of matrix solid-phase dispersion (MSPD) without heating. The possible conversion of C1/2 and GTX2/3 standards after heating, and the stability of PSTs in wet scallop tissues stored at -20°C for a 6-month period are also explored. Results showed that the MSPD technique could effectively mitigate matrix interference, but its recoveries of PSTs were significantly lower than those of the HCl and AcOH extraction methods followed by carbon SPE purification. The molar concentrations of M-toxins obtained by the MSPD method were generally lower than those analyzed by the HCl and AcOH extraction methods, which demonstrated a weak chemical conversion of C1/2 and GTX2/3 due to the heating process. Most of the PSTs were relatively stable in scallop tissues during 1-month storage at -20°C, while the concentrations of PSTs in scallop tissues obviously changed after 6 months due to the degradation and transformation of PSTs during long-term storage at -20°C. This work helps improve our understanding of the performance of different extraction methods and the stability of PSTs in scallop tissues stored at -20°C.

Effect of Ethanol Extract of the Fruiting Bodies of Pleurotus Ostreatus on Serum Lipid Profile and Atherogenic Indices of HS-HFD-STZ Induced Diabetic Rats

The effect of ethanol extract of the fruiting bodies of Pleurotus ostreatus on serum lipid profile and atherogenic indices of high sucrose high fat diet streptozotocin (HS-HFD-STZ) induced diabetic rats was determined by standard methods. All the groups were fed high sucrose-high fat diet except the normal group. The Metformin HCl and ethanol extract was given once daily by gavage to the reference and experimental groups respectively at doses of 150mg/Kg b.w., 50mg/Kg b.w, 150mg/Kg b.w. and 300mg/Kg b.w. respectively while the normal control received saline solution. The HDL-cholesterol level was higher than the value of the disease group after 6 weeks of administration of extract at 300mg/kg and after 9 weeks administration of extract at 150mg/kg. HDL cholesterol concentration increased by 22.2% after 6 weeks of extract administration at 300mg/kg and by 16.7% and 28.3% respectively after 9 weeks of extract administration at 150mg/kg and 50mg/kg respectively, indicating that the POE extract has the capacity to reduce cardiovascular diseases. At all the doses of extract administered for treatment at 3 weeks, 6 weeks and 9 weeks intervals, there was dose and time dependent lowering of LDL: HDL ratio even below the recommended risk limit of ≤ 2.5 compared to the test control with value above 2.5. After 3 weeks of treatment with extract at administration concentration level of 150mg/kg, atherogenic indices were lowered and extract levels of 150mg/kg and 300mg/kg reduced atherogenic index value after 6 weeks of administration while after 9 weeks of treatment, extract at 150mg/kg concentration reduced atherogenic indices. The atherogenic indices of the diabetic animals under treatment were dose-and time dependently reduced by POE treatment as observed in this study.These results suggest a possible use of the extracts in the management of hyperlipidemic conditions, hypertension and associated complications.

Antihyperglycemic Effect Of Ethanol Extract Of Fruiting Bodies Of Organically Cultivated Pleurotus Ostreatus In High Sucrose High Fat Diet Streptozotocin Induced Diabetes In Rats

The effect of ethanol extract of the fruiting bodies of Pleurotus ostreatus (POE)and metformin Hydrochloride on the body weight and blood glucose profile of high sucrose high fat diet streptozotocin induced diabetic rats was investigated. The experimental model was 20% High Sucrose (HS) + 20% High Fat Diet (HFD) + 35mg/kg body weight (via intraperitoneal) streptozotocin (STZ) induced diabetic rat model, with the fruiting body ethanol extracts administered orally at 50, 150 and 300mg/kg .The Metformin HCl and ethanol extract was given once daily by intragastric gavage to the reference and experimental groups respectively at doses 150mg/Kg b.w., 50mg/Kg b.w, 150mg/Kg b.w. and 300mg/Kg b.w. respectively while the normal control received saline solution for 88days . POE caused significantly dose – (p<0.05) and time dependent reduction (p<0.05) in blood glucose levels of HS-HFD-STZ- induced diabetic rats. The blood glucose concentration of diabetic rats indicated a tendency to normal levels after administration of POE at 300mg/kg and 50mg/kg respectively but metformin HCl, (150mg/kg b.w,) showed a greater blood glucose level reduction effect in 9weeks of treatment. Ethanol extract of Pleorotus ostreatus significantly (p<0.05), dose and time dependently restored body weights and blood glucose of rats. Results highlighted show that ethanol extracts of organically cultivated mushroom has anti-diabetic properties, suggesting that people may use it in medicinal formulation processes for the management of diabetes mellitus and its associated complications.

Aluminum extraction from a metallurgical industry sludge and its application as adsorbent

The aluminum industry produces a high number of wastes that are concentrated in the sludge of their water treatment plants. This sludge is rich in aluminum, which could be extracted and purified. In this work, three extraction methods have been evaluated to recover the aluminum from the sludge samples provided by a metallurgical industry from Medellín, Colombia. The sludge has been characterized to confirm its high aluminum content. The Bayer extraction method has been carried out, using 1:10, 1:15 and 1:20 sludge/solution mass ratios, and HCl extraction, by using 1:15 and 1:20 ratios. The extraction with isopropanol has also been evaluated. The amounts of Al, Fe, Cu, and Ni present in the aqueous phase have been measured to determine the recovery of the metals, as well as the selectivity of the extraction method. The highest metal recovery (99.3%) is achieved by HCl extraction for a sludge/solution ratio of 1:20, while the Bayer method (1:15 ratio) has shown the best selectivity. On the other hand, the extraction with isopropanol has not been successful for any of the ratios evaluated. The extracted material has been tested as an adsorbent for the removal of chlorpyrifos (200 mg l−1), where the removal percentages have been higher than 95% for all the weight ratios studied. Hence, this Al-enriched material shows good prospects to be used as an adsorbent in the treatment of polluted water.

Extraterrestrial hydroxy amino acids in CM and CR carbonaceous chondrites

AbstractThe abundances, distributions, and enantiomeric ratios of a family of three‐ and four‐carbon hydroxy amino acids (HAAs) were investigated in extracts of five CM and four CR carbonaceous chondrites by gas chromatography‐mass spectrometry analyses. HAAs were detected in both the acid hydrolysates of the hot water extracts and the 6 M HCl extracts of all the CM and CR chondrites analyzed here with total hot water and HCl extractable HAA concentrations ranging from 6.94 to 315 nmol g−1. The HAA analyses performed in this study revealed: (1) the combined (hot water + HCl) extracts of CR2 chondrites contained greater abundances of α‐HAAs than that of CM2 chondrites and (2) the combined extracts of CM and CR chondrites contained roughly similar abundances of β‐ and γ‐HAAs. Application of the new GC‐MS method developed here resulted in the first successful chromatographic resolution of the enantiomers of an α‐dialkyl HAA, d,l‐α‐methylserine, in carbonaceous chondrite extracts. Meteoritic α‐methylserine was found to be mostly racemic within error and did not show l‐enantiomeric excesses correlating with the degree of aqueous alteration, a phenomenon observed in meteoritic isovaline, another α‐dialkyl amino acid. The HAAs identified in CM and CR chondrite extracts could have been produced during parent body alteration from the Strecker cyanohydrin reaction (for α‐HAAs) and an ammonia‐involved formose‐like reaction (for β‐, and γ‐HAAs).

Evaluasi Kesuburan Tanah Ultisol pada Pertanaman Karet di Kecamatan Cempaka Kota Banjarbaru, Provinsi Kalimantan Selatan

Rubber is one of the mainstay commodity plantations that plays a role in the national economy, including in the economy of South Kalimantan Province. The purpose of this study was to determine the fertility status of Ultisols in rubber plantations in Cempaka District, Banjarbaru City, South Kalimantan Province. Using a survey method, the rubber planting location was determined through purposive sampling. Observation variables include pH H2O 1:5; cation exchange capacity, CEC (me / 100 g) and base saturation, KB (%) 1N NH4OAc extract pH 7.0; P-total (mg / 100g) and K-total (mg / 100g) 25% HCL extract; and the C-organic (%) Walkey and Black method. The soil fertility status was determined according to PPT, 1995. The results showed that Ultisol soil in rubber plantations in Cempaka District, Banjarbaru City, South Kalimantan Province had low fertility status. This low fertility status is due to the nature of the soil which has acid criteria, a pH of 4.90; KTK is classified as medium criteria, amounting to 18.78 me / 100 g; KB is classified as very low, amounting to 9.99%; P-Total classified as low, a number of 4.63 (mg / 100g); K-Total classified as low, worth 16.32 (mg / 100g); and C- Organic which is included in the moderate criteria, amounting to 2.11%. This study revealed that the main inhibiting factors for soil fertility in rubber plantation in Cempaka District were pH, KB, P-total, and K-Total. To improve soil fertility status, calcification, addition of organic matter, and fertilization can be carried out.

Effects of chemical pre-treatments on modified starch granules: Recommendations for dental calculus decalcification for ancient starch research

Starch granules and other plant microremains embedded in dental calculus provide information about the diet and culinary practices of past individuals. While most researchers use either hydrochloric acid (HCl) or ethylenediaminetetraacetic acid (EDTA) to demineralise samples and release embedded microremains, protocols vary significantly in regard to chemical concentration and duration. Furthermore, there are conflicting reports concerning the suitability of these chemicals for archaeological starch analyses, particularly when granules are modified (damaged) such as from food processing or enzymatic digestion. This study tests 0.5 M HCl and 0.5 M EDTA on modified modern wheat, chickpea and potato starch with direct observation of individual starch granules over 168 h, the maximum duration reported so far for full decalcification of archaeological calculus samples. While there were no observable changes to gross morphological characteristics of any granules, metric analysis indicates slight changes to average granule size in milled potato and wheat starch in all solutions. Furthermore, interactions between the chemical reagent and ions released from the calculus matrix have the potential to result in the diminished recovery of archaeological starch from HCl extractions. We recommend that of these two chemical decalcification options, EDTA is more suitable for processing archaeological dental calculus for starch microremains as it chelates ions released during decalcification of the calculus matrix that might otherwise adversely affect archaeological starch granules.

Gaseous ozone treatment of chickpea grains, part I: Effect on protein, amino acid, fatty acid, mineral content, and microstructure

The effect of gaseous ozone (500–1000 ppm) treatment on the protein, amino acid, and fatty acid profiles, mineral content, and the microstructure of the chickpea grains were evaluated. Though protein content was not altered significantly, SDS PAGE profiling exhibited minor modifications in the protein bands of the treated chickpea. The essential amino acids (EAA) and total amino acids (TAA) slightly decreased, ratio of EAA to TAA increased, while the calculated protein efficiency ratio decreased. Significant decrease in the SH content and non-significant increase in SS content was observed at higher doses of ozone. The overall saturated and unsaturated fatty acids (%) were in the range of 13.05–13.49 and 86.51–87.61, respectively. The minerals were stable and the HCl extractability decreased in the ozonated samples. There was some minor degradation of intracellular cell wall and distribution of starch and protein bodies in the ozonated sample.

Comprehensive assessment of heavy metal pollution and ecological risk in lake sediment by combining total concentration and chemical partitioning.

Total concentration and chemical partitioning of heavy metals are commonly used in environmental quality assessment; however, their comparability and comprehensive application are far less discussed. Herein, bioavailability, pollution and eco-risk of As, Cd, Cr, Cu, Ni, Pb and Zn in surface sediments of Erhai Lake were evaluated referring to multiple indices following the experimental methods of complete digestion, optimized Community Bureau of Reference (BCR) and 1.0M HCl extractions. Results of bioavailability for most metals were similar and comparable from BCR and HCl extractions. While bioavailable concentrations of Cd and Pb from HCl extraction were significantly (p<0.01) lower than those from BCR extraction, indicating BCR extraction is more efficient. Results of enrichment factor (EF) and concentration enrichment ratio (CER) suggested that Cd was the highest polluted element followed by As, Pb and Zn, whereas Cr, Cu and Ni were mainly natural in origin. Similar concentrations of anthropogenic As from EF and CER assessments indicated anthropogenic As mainly existed in bioavailable form. However, anthropogenic Cd, Pb and Zn existed in both bioavailable and residue forms, resulting in the underestimation of anthropogenic metals by the CER assessment. The sediment quality guidelines (SQGs), potential ecological risk index (Er) and risk assessment code (RAC) showed inconsistent eco-risks for each of the metals except Cd. Combining pollution level and chemical partitioning with SQGs, Er and RAC assessments, high eco-risk of Cd, moderate eco-risk of As and Pb, and low eco-risk of Cr, Cu, Ni and Zn were graded. Our study highlights the limitation of single index and the necessity of integrating multiple indices following total concentration and chemical partitioning in metal pollution and eco-risk assessments.

The Release of a Soluble Glycosylated Protein from Glycogen by Recombinant Lysosomal α-Glucosidase (rhGAA) In Vitro and Its Presence in Serum In Vivo.

In studies on the degradation of glycogen by rhGAA, a glycosylated protein core material was found which consists of about 5–6% of the total starting glycogen. There was an additional 25% of the glycogen unaccounted for based on glucose released. After incubation of glycogen with rhGAA until no more glucose was released, no other carbohydrate was detected on HPAEC-PAD. Several oligosaccharides are then detectable if the medium is first boiled in 0.1 N HCl or incubated with trypsin. It is present in serum either in an HCl extract or in a trypsin digest. The characteristics of the in vivo serum material are identical to the material in the in vitro incubation medium. One oligosaccharide cannot be further degraded by rhGAA, from the incubation medium as well as from serum co-elute on HPAEC-PAD. Several masked oligosaccharides in serum contain m-inositol, e-inositol, and sorbitol as the major carbohydrates. The presence of this glycosylated protein in serum is a fraction of glycogen that is degraded outside the lysosome and the cell. The glycosylated protein in the serum is not present in the serum of Pompe mice not on ERT, but it is present in the serum of Pompe disease patients who are on ERT, so it is a biomarker of GAA degradation of lysosomal glycogen.

A Site-Specific Fertilizer Recommendation Based on the Phosphorus and Potassium Status in Mempawah District, West Kalimantan

The recommendations of Phosphorus (P) and Potassium (K) fertilization for rice are still not site-specific yet due to a lack of required soil data information. The P and K status of the paddy fields that provide information on the low, medium, and high P and K nutrient status are very useful for determining recommended the site-specific fertilizer in the the district area. The purpose of the research was to determine the site-specific fertilizer recommendation for paddy field based on their P and K status. This research was based on the field survey and the soil analysis in the laboratory. The soil samples were taken using a grid system, and the P and K levels were assessed by using a 25% HCl extraction. Soil samples were taken in a composite manner on all paddy fields in which their status have been identified. The composite soil samples were determined from 10 - 15 individual samples (sub-samples) with a sampling distance of each sub-sample of 25-50 m in the field. The soil samples were taken in the overlay with a depth of 0-20 cm. Taking sub-samples were done by a diagonal or a zigzag method according to the conditions of paddy fields. The results of the study presented that the nutrient status of P and K and the fertilizer recommendations in paddy fields for rice plants located in 9 sub-districts in Mempawah Dsitrict had shown that nutrient status of P, on average, were from moderate to high levels, meanwhile, the nutrient status of K was from low to high levels. Recommendations for fertilizing rice fields in several sub-districts in Mempawah Regency are mostly 150 kg NPK (15:15:15) ha-1, 200 kg Urea ha-1 and 25 kg KCl ha-1.

Crude Fucoidan Activity Extracted from Sargassum &lt;i&gt;sp&lt;/i&gt;. as Mycotoxin (T-2) Binder

Fucoidan is a sulfated polysaccharide which is mainly found in brown seaweed like Sargassum sp. In this study, fucoidan was extracted with two distinct methods, one was using 0.1 N HCl (Fucoidan A) and the other 0.1 N H3PO4 (Fucoidan B). The yield of HCl extraction was respectively 7.50% and H3PO4 extraction 7.02%. Characterization of crude fucoidan was carried out through fourier-transform infrared spectroscopy (FTIR), followed by total carbohydrate and total sulfate level measurement. Crude fucoidan was then used to determine its binding activity against Trichothecenes T-2 toxin. Quantitative analysis of 50 ug/ml T-2 toxin binding capacity shows an efficiency of 59.52% at pH 3.0 and 58.37% at pH 6.8 for crude fucoidan A. As for crude fucoidan B, efficiency of T-2 toxin binding capacity has value of 58.12% at pH 3.0 and 57.33% at pH 6.8. Meanwhile, Commercial crude fucoidan extract from Fucus vesiculosus sp. was used as control for T-2 toxin binding capacity analysis with efficiency of 57.31% at pH 3.0 and 56.64% at pH 6.8. Therefore, fucoidan from Sargassum sp. can be utilized better as mycotoxin especially T-2 toxin binder than from Fucus vesiculosus sp. through efficiency result of fucoidan binding capacity.

Effects of curing temperature on the compressive strength and microstructure of copper tailing-based geopolymers

This study sought to analyze the effect of curing temperature on mechanical strength and microstructure of a copper tailing-based geopolymer via scanning electron microscopy (SEM), HCl extraction, nuclear magnetic resonance (NMR), and X-ray diffraction (XRD). The distribution of gel formed in geopolymers tended to be uniform with increasing curing temperature from 25 to 80 °C. Moreover, the percentage of Si sites in C–S–H and N-A-S-H gels increased from 62.08% to 78.94% and more tetrahedral [AlO4] was incorporated into the tetrahedron [SiO4] backbone, leading to an increase of compressive strength from 10.2 to 39.6 MPa. When the curing temperature was increased to 120 °C, the percentage of Si sites in C–S–H and N-A-S-H gel decreased to 69.52%, and the compressive strength decreased to 27.5 MPa. Moderately elevated curing temperature promoted the dissolution of aluminosilicate while curing temperatures above 80 °C hindered it. Excessive curing temperature led to a decrease in the geopolymer alkaline medium.