mL Of Solvent Research Articles

An effective "precursor-transformation" route toward the high-yield synthesis of ZIF-8 tubes.

An effective "precursor-transformation" route was developed for the high-yield synthesis of ZIF-8 tubes based on the reaction of 1D Zn-EG (ethylene glycol) wires with 2-methylimidazole (with around 0.6 g of ZIF-8/60 mL of solvent, the yield is over 90% based on Zn). The ZIF-8 tubes fixed on a sponge can be used as an effective material for oil/water separation.

Dry washing biodiesel purification using fumed silica sorbent

Aiming the decarbonization of the transport sector, biodiesel, obtained by alcoholysis of oils or animal fats, is currently mixed with conventional fossil diesel. For this purpose, biodiesel has to comply with the established quality standards and, therefore, the production process comprises purification steps, which need huge volumes of water. Thus, the biodiesel purification procedure must be improved in order to provide a greener and low-cost renewable fuel.Biodiesel (FAME) produced by methanolysis of soybean and waste frying oils over a heterogeneous calcium-based catalyst was purified by dry washing, using commercial silica sorbent (Sipernat 22 from Evonik). ATR-FTIR spectra of post-purification sorbents showed that silica was effective to remove unreacted oil species, glycerin and Ca soap from biodiesel and, contrary to the previously reported in the literature, it was also able to remove leached calcium from the biodiesel. For both feedsotcks, the highest purity was reached for the sorption test carried out at 45 ℃ during 60 min.Sorbent regeneration was evaluated using acetone, methanol, and isopropanol alcohols at room temperature during short contact time (5 min for 1 g of sorbent and 20 mL of solvent). All the tested solvents were effective to remove the adsorbed species from silica surface.

Application of piper betel leaf (piper betle linn) extract to control fish pathogenic bacteria in-vitro

Betel leaf extracts have some natural antimicrobial. This extracts has been used as antimicrobial agent in some aqua farmer in Indonesia for an alternative method to control fish diseases. This study aims to determine the effects of betel leaf extract on fish pathogenic bacteria in-vitro. Three kinds of solvents were used in betel leaf extracts. There were ethanol, n-hexane and ethyl-acetate. About 100 g of betel leaf simplicia were diluted by 1000 ml of solvents in stainless container cap for 24 hours maceration. This extracts were filtered with 0.42 μm paper filter and then evaporated at 50C during 30 minutes in 50 rpm with vacuum rotary evaporator. This concentrated extracts were used to antimicrobial testing. The pathogenic bacteria for in-vitro testing were from Gram-negative bacteria such as Aeromonas hydrophila, Vibrio alginolyticus and Edwardsiella tarda. The in-vitro test of herbal extract from betel leaf againts Gram-negative pathogenic bacteria indicated that the betel leaf extract could inhibited the growth of pathogenic bacteria with diameter mean of inhibition zone were more than 14 mm. The solvents variations were not significantly different (p > 0.05) to diameter inhibition zone of V. alginolyticus and A. hydrophila but significantly different (p < 0.05) to E. tarda.

Development and validation of ultrasound assisted extraction (UAE) and HPLC-DAD method for determination of polyphenols in dry beans (Phaseolus vulgaris)

An analytical method for extraction and quantitative determination of the main phenolic compounds (hydroxycinnamic acids and derivatives, anthocyanins and flavonols) in dry beans (Phaseolus vulgaris) is described. The best extraction conditions were: 100% sonication amplitude, 10.3 min extraction, 46% ethanol, 1.5 g dry bean flour and 30 mL of solvent. The developed method was validated in terms of accuracy and precision. Good linearity was obtained, with correlation coefficients exceeding 0.999 and the quantification limits ranged from 0.25 μg/g (p-coumaric acid) to 1.38 μg/g (kaempferol). The accuracy ranged between 88 and 92% and the reproducibility of the method was always < 5.8% (RSD). The method was applied to a set of 17 accessions with different phenotypes. Results showed a greater presence, in all cases, of ferulic acid derivatives, compared to the sinapic acid and p-coumaric acid derivatives. Except for the white variety Xana, flavonoids were detected in all samples. Higher levels of anthocyanins were detected in Black Turtle Soup, a black bean, characterized by a higher content of delphinidin 3-O-glucoside, petunidin 3-O-glucoside and malvidin 3-O-glucoside. The flavonols showed a remarkable diversity, the 3-glucoside derivatives being the most abundant in all samples.

Microwave-Assisted Extraction of Ricinine from Ricinus communis Leaves.

The alkaloid ricinine (3-cyano-4-methoxy-N-methyl-2-pyridone) is found in different parts of the Ricinus communis plant and is known to possess several bioactive properties, including strong antioxidant activity. In this study, a new microwave-assisted extraction (MAE) method was developed for the recovery of ricinine from R. communis leaves. The extraction variables studied were extraction temperature (between 125 °C and 175 °C), microwave power (between 500 W and 1000 W), extraction time (between 5 min and 15 min), extraction solvent (between 10% and 90% of EtOAc in MeOH), and solvent-to-sample ratio (between 25:1 mL and 50:1 mL of solvent per gram of the sample). On studying the effects of extraction variables, both solvent and liquid-to-solid ratio were found to exhibit the highest effects on ricinine recovery. A fast (15 min) microwave-assisted extraction method was developed (high temperatures can be applied because the stability of ricinine is proven in the literature), allowing for the recovery of ricinine from R. communis leaves. The study revealed that R. communis leaves had almost 1.5 mg g−1 (dried weight) of ricinine.

Cortisol Extraction from Sturgeon Fin and Jawbone Matrices

The aims of this study were to develop a technique for the extraction of cortisol from sturgeon fins using two washing solvents (water and isopropanol) and quantify any differences in fin cortisol levels among three main sturgeon species. Fins were harvested from 19 sacrificed sturgeons including seven beluga (Huso huso), seven Siberian (Acipenser baerii), and five sevruga (A. stellatus). The sturgeons were raised in Iranian farms for 2 years (2017-2018), and cortisol extraction analysis was conducted in South Korea (January-February 2019). Jawbones from five H. huso were also used for cortisol extraction. Data were analyzed using the general linear model (GLM) procedure in the SAS environment. The intra- and inter-assay coefficients of variation were 14.15 and 7.70, respectively. Briefly, the cortisol extraction technique involved washing the samples (300 ± 10 mg) with 3 mL of solvent (ultrapure water and isopropanol) twice, rotation at 80rpm for 2.5 min, air-drying the washed samples at room temperature (22-28 °C) for 7 days, further drying the samples using a bead beater at 50 Hz for 32 min and grinding them into powder, applying 1.5 mL methanol to the dried powder (75 ± 5 mg), and slow rotation (40 rpm) for 18 h at room temperature with continuous mixing. Following extraction, samples were centrifuged (9,500 x g for 10 min), and 1 mL supernatant was transferred into a new microcentrifuge tube (1.5 mL), incubated at 38 °C to evaporate the methanol, and analyzed via enzyme-linked immunosorbent assay (ELISA). No differences were observed in fin cortisol levels among species or in fin and jawbone cortisol levels between washing solvents. The results of this study demonstrate that the sturgeon jawbone matrix is a promising alternative stress indicator to solid matrices.

Optimization of ultrasonic-assisted extraction of kahweol and cafestol from roasted coffee using response surface methodology

Kahweol and cafestol were extracted by ultrasound-assisted extraction, replacing the conventional liquid: liquid method. Three parameters of extraction were investigated: amplitude level (41, 102. 5 and 164 μm), extraction time (2, 4 and 6 min) and solvent volume (2, 4 and 6 mL). All parameters had a significant effect on the extraction (p < 0.05). Higher amplitude (164 μm) and volume near the central point (4 mL) significantly increased kahweol and cafestol contents. The process time effect was differentiated for each diterpene. Optimum conditions for diterpene simultaneous extraction was chosen: 164 μm, 4 mL of solvent and 6 min-extraction. Scanning electron microscopy images showed that the ultrasound treatment caused a physical modification in the matrix. The kahweol and cafestol contents obtained by sonication were lower compared to the observed for liquid/liquid extraction (13% for kahweol and 3% for cafestol). However, sonication had a positive impact, intensifying and accelerating the process. The use of sonication allowed the extractive process to be simplified, reducing the number of stages (two steps compared to the conventional method), the amount of solvent and the analysis time.

Optimization of Solvent Extraction of Oil from Watermelon (Citrullus lanata) and its Fatty Acid Characterization

Watermelon also known as Citrullus lanata is one of the major underutilized fruits grown in the warmer part of the world. Over the years, with respect to the high rate of production of watermelon along with lack of consciousness of the benefits, its seed has suffered negligence and consequently become waste. Due to the growing awareness of the usage of seed oil; there is need to maximize the use and identify the appropriate sets of parameters necessary for the optimum extraction of the oil. This research looked at the parametric effect of hot continuous extraction process at 60-700Cfor watermelon seed using response surface methodology, Box Behnken design with 3 variables which are time of extraction, solvent volume and size particle of 30-50 mins, 100-200 ml and 4-10 μm respectively. The optimized solution indicates that the time of extraction of 50 mins, 199.99 ml of solvent with 10 μm of size particle give the maximum oil yield of 68% compared to the maximum experimental oil yield of 52.5%. Free fatty acid (FFA) content in the oil was determined using (Analysis of the Association of Official Analytical Chemists), 2000 method which gives 17.35%, (higher than 1.0% standard) indicating the need to reduce the FFA content in the oil before the production of biodiesel to avoid low fatty methyl ester (FAME) production against high soap formation.

Biomolecules Derived from Carissa edulis for the Microwave Assisted Synthesis of Ag2O Nanoparticles: A Study Against S. incertulas, C. medinalis and S. mauritia

The green method for metal nanoparticles has been gaining more interest owing to its low cost and safe nature. The Carissa edulis (C. edulis) dried fruit extract was utilized for the synthesis silver oxide nanoparticles (Ag2O NPs). The microwave extraction process was optimized using Box-Behnken Design (BBD). The good optimization was found to be 400 W, 70 °C and 30 mL of solvent. We have observed 0.17 g of extract yield from this method. The green synthesized Ag2O NPs were analyzed by various analytical techniques. The absorption peak around 420 nm confirms the formation of Ag2O NPs. Further, the SEM and TEM results showed cube and ellipsoid shape with 1.5–2 nm. The Photocatalytic of Ag2O NPs showed 95.8% of degradation of Congo red with rate constant of 0.0233 min−1 and the antibacterial activity of Ag2O NPs was showed high zone of inhibition (10 mm) against E. coli. Therefore, C. edulis extract mediated Ag2O NPs can be used to carry further research in environmental science and biotechnology.

An experimental investigation of nanoemulsion enhanced oil recovery: Use of unconsolidated porous systems

Utilization of nanoparticles in oil and gas industry has attracted considerable attention of engineers and researchers. In this article, the feasibility of nanoemulsion flooding is investigated as a method for Enhanced Oil Recovery (EOR) through coreflooding experiments, using a packed bed and real reservoir fluids. Nine different mixtures of the solvent, surfactant, and nanoparticles in the form of a nanoemulsion phase are generated and used to recover the oil in the context of an EOR process. Various tests are conducted to determine the properties of porous medium and fluids. To study the production performance of this EOR technique, pressure drop across the packed bed are measured, along with the volumetric measurements of the produced fluids. A baseline injection scheme using seawater is also performed. All the nanoemulsion fluids are synthesized using the same base seawater. The Taguchi experimental design approach is employed in this research to design the experiments. The effects of nanoparticles concentration, along with those of surfactant and solvent components of the injection fluid on the oil recovery at the laboratory scale are investigated using the Analysis of Variance (ANOVA) method. Comparing the performance of waterflooding (WF) and nanoemulsion flooding, enhancement in the Recovery Factor (RF) by using emulsions is between 40–107%. Both the pressure and pressure fluctuations are surprisingly higher in the case of WF in comparison to the emulsion flooding. It is also found that under optimal concentration conditions (0.01 g of nanoparticles, 0.015 mL of surfactant, and 1 mL of solvent per one liter of brine), a recovery factor of up to 60% is achieved.

Development and validation of an LC-MS/MS method for the analysis of ivermectin in plasma, whole blood, and dried blood spots using a fully automatic extraction system

Ivermectin is deployed in mass drug administration (MDA) campaigns to control parasitic diseases in the tropics, with billions of treatments having been administered in the last three decades. Simple blood sampling tools, like the dried blood spots (DBS) technique, are needed to monitor treatments in such challenging settings. Thus, we developed a fully automated method for the analysis of ivermectin in DBS microsamples, including a bioanalytical and clinical validation.Automated extraction was carried out using a DBS-MS 500 autosampler which was coupled to a LC–MS/MS system. DBS were extracted with 20 μL solvent and eluted on a C8 analytical column. Analysis was performed by multiple reaction monitoring in the positive mode.Automated DBS extraction resulted in consistent recoveries (62.8 ± 4.3%) and matrix effects (68.0 ± 8.1%) between different donors and concentration levels. Intra- and inter-day accuracy and precision deviations were ≤15%, while samples with hematocrits from 20 to 60% could be quantified reliably. The achieved sensitivity of 1 ng/mL in DBS samples is sufficient to analyze ivermectin at the dose given (single oral administration of 12 mg) over a period of at least 72 h post treatment. Importantly, DBS samples are stable after one-month storage at room temperature (accuracy: 88.8–96.2%), thus samples collected in the field must not be shipped on dry ice. Ivermectin concentrations in venous and capillary blood agreed strongly, with a mean difference of −4.8%. Moreover, the drying process of DBS did not alter the analysis and importantly plasma concentrations can be estimated from DBS data using the hematocrit and red blood cell partitioning as correction factor.Our method enables uncomplicated sample collection and shipment as well as automated analysis of large amounts of samples, which is key to surveying MDA campaigns in remote settings.

Optimization of Nepeta Cataria Essential Oil Extraction Yield by Ultrasonic-Soxhlet Extraction Method Using Response Surface Methodology

Essential Oil (EO) of Nepeta Cataria L. has an attractive benefit due to its potential as alternatives compound of controlling mosquito vectors especially Aedes aegypti. This paper reports on application of response surface methodology (RSM) using Box Behnken design (BBD) to optimize the extraction of EO from Nepeta Cataria L. The parameters experimented were the time of extraction (120-360 min), temperature of sonication (30-50°C) and ratio of sample to solvent (30-60gram/150ml). The extraction was conducted by using soxhlet method assisted by ultrasound using ethanol (polar solvent). Statistical analysis and analysis of variance indicated that the time of extraction and ratio of sample to solvent are significant factors (p<0.05) affecting the yield while the temperature of sonication was insignificant (p>0.05). For the modelled extraction, the minimum critical values for ethanol solvent was 269.48 minute, 40.18°C and 33.22 gram/150 ml ethanol. Recovery of oil when 1 gram of raw material was used per 150 ml of solvent was 2.32%. By using High Performance Liquid Chromatography with Ultraviolet detector (HPLC-UV), nepetalactone was detected at time of 12.694 min and 13.941 min using absorption peak 228nm.

Conductive Polymer Spray Ionization Mass Spectrometry for Biofluid Analysis.

We present a conductive polymer spray ionization (CPSI) method for the direct mass spectrometric analysis of hydrophilic drugs, saccharides, peptides, and proteins in biofluids. Carbon nanotubes (CNTs) were introduced into poly(methyl methacrylate) (PMMA) to fabricate a conductive composite substrate CNT/PMMA in the shape of a triangle (8 mm wide and 10 mm long) with its apex pointed toward the inlet of a mass spectrometer. In comparison with a traditional paper spray substrate, the conductive polymer absorbs less hydrophilic compounds owing to its hydrophobic nature. When aqueous biofluid samples are loaded, they also exhibit less diffusion on this nonporous surface. Only 1.0-2.0 μL solvent suffices to extract the components in a dried biofluid spot and to form charged microdroplets (4.5 kV high voltage applied). Furthermore, the hydrophobic polymer surface only needs to overcome weak surface tension to emit charged microdroplets, so that the signal has a typical duration of 7.5 min. For sunitinib, acarbose, melamine, and angiotensin II, the ion intensity of the target compound from the conductive polymer support is significantly higher than paper spray, typically by a factor of 20 to 100. These results suggest that the CNT/PMMA conductive polymer spray has great potential in the analysis of hydrophilic drugs, saccharides, peptides, and proteins in biofluids.

Microwave-assisted solvent extraction of castor oil from castor seeds

Abstract This study was aimed at evaluating the physicochemical properties and oxidation stability of castor oil using microwave-assisted solvent extraction (MAE). MAE was performed using 5% ethanol in hexane as solvent at different extraction times, power intensities and solvent-to-feed (S/F, ml of solvent to gram of feed) ratios. The process parameters were optimized by statistical approach using historical data design of response surface method (RSM). The oils were characterized for yield, physicochemical properties, dielectric properties and oxidation stability, and comparison was also made with oil extracted using Soxhlet method. Results show that the maximum oil yield of 37% was obtained at 20 min with microwave power intensity of 330 W and S/F ratio of 20. The main fatty acid composition of castor oil is ricinoleic acid. The density, refractive index, dielectric properties and oxidation stability of oils are not affected by the extraction methods and extraction parameters of MAE. However, the MAE-extracted oil is more viscous compared to that by Soxhlet method. With extra caution on oil oxidation, MAE could be a promising solvent extraction method with an 86% less in processing time and a higher yield.

Hypomethylation of specific CpG sites in the promoter region of steroidogeneic genes (GATA6 and StAR) in prenatally androgenized rats

IntroductionThe methylation level of promoters is one of the most studied and well-known epigenetic mechanisms that programs the amount of gene expression. Over expression of steroidogenesis genes via epigenetic control can result in hypetandrogenism, which is the main endocrine aspect of polycystic ovarian syndrome (PCOS). AimsIn the present study we aimed to determine and compare the promoter methylation levels of three steroidogenic genes, CYP17, GATA6 and StAR, in theca cells of prenatally androgenized (PNA) rats to those of controls. Materials and methodsPregnant Wistar rats in the PNA group received 5 mg free testosterone, dissolved in 500 ml solvent, subcutaneously injected on day 20 of pregnancy, while controls were injected with 500 ml of solvent only. Theca cell samples, taken from the ovaries of eight to ten female offspring of both the PNA and control groups, were measured for promoter methylation levels of the aforementioned genes, using the bisulfite sequence PCR (BSP) method. Key findingsAlthough the promoters of all three genes were slightly hypomethylated in the PNA group, the differences observed were not significant compared to the control group. The methylation of −520 and −822 positions, in the GATA6 and the StAR promoter respectively, were significantly decreased in the PNA group. SignificancesThe results of this study suggest that alterations in the steroidogenesis pathway after exposure to excess androgen may be a result of changes in the pattern of the methylation of the relevant genes.

Optimization and kinetic modeling of oil extraction from white mustard (Sinapis alba L.) seeds

White mustard seed oil (WMSO) was extracted from the ground seed by cold pressing and Soxhlet extraction using n–hexane. A two–step process consisting of cold pressing of white mustard seed (WMS) and extraction of WMSO from press cake (maceration) was also employed to improve the overall WMSO recovery. The main fatty acids of the WMSO were unsaturated oleic, eicosenoic, erucic, linoleic and linolenic acid. The maceration of press cake was modeled on the basis of a 33 full factorial design with replication coupled with the response surface methodology. The analysis of variance and the quadratic equation were used for assessing the significance of the influence of solvent–to–cake ratio, extraction temperature and extraction time on WMSO yield and for optimizing the maceration process. All three individual process factors, the interactions of extraction temperature with solvent–to–seed cake ratio and time as well as the quadratic terms of solvent–to–seed cake ratio and extraction time had a statistically significant influence on WMSO yield at the 95% confidence level. The mean relative percentage deviation of ±2.3% and the coefficient of determination of 0.923 proved the adequacy of the developed quadratic model for WMSO yield. The predicted and actual WMSO yields under the optimal maceration conditions (70 °C, 6.5:1 mL of solvent per g of seed cake and 5 min) were 7.29 and 7.20 ± 0.13 g/100 g, respectively. With the two–step process, the WMSO yield of 20.48 g/100 g was achieved, which was 99.2% of the WMSO yield obtained by Soxhlet extraction. This indicated that the two-step process could replace the energy- and solvent-intensive Soxhlet extraction of ground WMS. The model of instantaneous washing followed by diffusion described most adequately the kinetics of WMSO extraction from press cake in the applied experimental region. WMSO extraction from WMS press cake was shown to be as spontaneous, irreversible and endothermic.

Application of Carboxymethyl Chitosan-Benzaldehyde as Anticorrosion Agent on Steel

Corrosion is one of the problems that is often found in daily life especially in petroleum and gas industry. Carboxymethyl chitosan- (CMC-) benzaldehyde was synthesized as corrosion inhibitor for steel. Corrosion rate was determined by potentiostatic polarization method in HCl 1 M. Dripping and coating, two different treatment, were used to drop and coat steel by CMC-benzaldehyde. The results showed that CMC-benzaldehyde could inhibit the corrosion rate of steel with concentration of 1 g, 3 g, 5 g, and 7 g in 60 mL of solvent. Coating steel with CMC-benzaldehyde with concentration of 7 g/60 mL of solvent and starch of 0.1 g/mL showed the highest efficiency to inhibit corrosion rate of steel. These treatments give corrosion efficiency of 99.8%.

Optimisation of caffeine and antidepressants extraction from sediments and sewage sludge using experimental designs

ABSTRACTThis study proposes a microwave-assisted method for the simultaneous extraction of highly prescribed antidepressants (citalopram, venlafaxine, fluoxetine, sertraline and amitriptyline) and caffeine from sediments and sewage sludge for subsequent HPLC-PDA analysis. Because the sludge and sediment matrices have high contents of organic material, they strongly interact with the analytes and hinder extraction. Thus, a carefully optimised analytical methodology is required for quantitative extraction. A simplex-centroid design was applied to optimise the solvent composition, and a three-factor central composite rotational design was used to optimise the extraction protocol with regards to pH, amount of solvent and processing time. Samples (in triplicates) were fortified with a standard mixed solution of all the analytes and extracted according to the experimental design in each study. The extraction steps included: 30 s vortexing, 20 s microwave heating at 10 W, cooling to room temperature (25°C) in an ultrasonic bath for 60 s, 2 min centrifugation at 2000 rpm, and filtration. Analysis of variance and lack-of-fit tests were used to assess the significance of data fitting at 95% confidence. The desirability function was the optimisation tool used to obtain the ideal extraction conditions. As a result, a binary mixture of methanol and acetonitrile in 45:55 and 53:47 (v/v) ratios was indicated as the optimum solvent composition for the simultaneous extraction of all the target drugs from the sludge and sediment, respectively. The optimised extraction conditions were: 3 extraction cycles with 4 mL of solvent at pH 3 for sewage sludge extraction and 4 extraction cycles with 3 mL of solvent at pH 11 for sediment extraction. Further, low recoveries were obtained for extractions from sediment as compared to sludge indicating strong interaction of antidepressants and caffeine with the acidic organic components of sediments. It was found that the optimisation of pH of the extraction phase was crucial for the efficient extraction of the analytes from these environmental matrices.

Prediction of Experimental Measurement Data for High Density Polyethylene and Polypropylene Solubility in Organic Solvents

Abstract High density polyethylene (HDPE) and polypropylene (PP) solubility in several pure and blend non-polar organic solvents was measured at 365–430 K temperature at atmospheric pressure, with polymer concentration of 0.5–25 g in 100 ml of solvent. The activity coefficients were estimated depending on the experimental solubility results for all the polymer-solvent systems. A non-ideal equation combined with activity coefficient was developed based on the crystallinity. A new correlation equation was attained, which is based on the melting temperature and heat of fusion using SSPS software. These two equations were used to predict the solid-liquid experimental data for the binary system polymer-solvent. The distinction between the experimental and model data was assessed by using mean absolute deviation percentage (MAD %). The non-ideal equation based on crystallinity and the new correlations showed low MAD %, displaying a close match with the experimental data.

PENGUJIAN ZAT WARNA DARI EKSTRAK BUAH NAGA (HYLOCEREUS POLYRHIZUS) DAN CENGKODOK (MELASTOMAS MALABATHRICUM) SEBAGAI INDIKATOR ALAMI

ABSTRACT The purpose of this research was to test the dye on extracts of dragon fruit (Hylocereus polyrhizus) and cengkodok (Melastoma malabathricum) as a natural indicator. This natural indicator was made by utilizing the content of the dye (anthocyanin) in plants which have fruit or flowers. Maseration was conducted by using two solvents consist of aquadest and ethanol to determine which one of the best solvent. Aquadest solvent showed as the best extractor for dragon fruit. Meanwhile ethanol solvent as the best extractor for cengkodok (70%). The best composition of the dragon fruit and cengkodok was 1:1 of solvent meanth 1 gram of dragon fruit or cengkodok was dissolved in 1 ml of solvent. The best soaking time of dragon fruit and cengkodok was 90 minutes. Test the pH range in a solution of pH 1-14 for dragon fruit gave pH from 1 to 4 as a pH indicator stretch natural, and for cengkodok gave pH from 11 to 14 as a pH indicator stretch natural.Keywords: cengkodok, dragon fruit, natural indicator, pH range