Penetapan Kadar Tanin pada Teh Hitam Kering Produksi Pekalongan dengan Metode Spektrofotometri UV-Vis

Tea plants have benefits as antioxidants and help protect body cells from the bad effects of free radicals. The content in dried black tea leaves has tannin compounds that have a good effect on the body. The purpose of this study was to determine the difference in tannin levels in dry tea produced by Pekalongan with UV-Vis Spectrophotometry and to find out that all samples of tea brands met the requirements for consumption limits in tea. The data obtained were the average tannin content of black tea leaf extract from various samples with concentrations used of 8, 16, 24, 32, and 40 g/ml. Data analysis to determine the tannin content using the standard curve method, linear regression y = a + bx. The results obtained from the TLC qualitative test contained sample and comparison spots at UV 254 nm, namely Rf T1 of 0.84 cm, T2, T4, T5, T8, T9 of 0.85 cm, on samples T3, T7, T10, T11 obtained an Rf value of 0.86 cm which has the same Rf value as the comparison of catechins. and the sample T6 obtained an Rf value of 0.81 cm. As for the quantitative test, the highest levels were obtained in samples T1, T3, T6, T8, T10 as much as 0.004 ± 0 g/g while the lowest levels were obtained in samples T2, T4, T5, T7, T9, T11 as much as 0.003 ± 0 g/g It can be concluded that the circulating tannins produced by Pekalongan meet the consumption limit requirements.Keywords: Content; Tea; Tannins; UV-Vis Spectrophotometry AbstrakTanaman teh memiliki manfaat sebagai antioksidan dan membantu melindungi sel-sel tubuh dari efek buruk radikal bebas. Kandungan pada daun teh hitam kering mempunyai senyawa tanin yang memberikan efek baik bagi tubuh. Tujuan penelitian ini mengetahui adanya perbedaan kadar tanin pada teh kering produksi Pekalongan dengan metode Spektrofotometri UV-Vis dan mengetahui semua sampel merk teh memenuhi persyaratan batas konsumsi dalam teh. Data yang didapatkan adalah data rata-rata kadar tanin dari ekstrak daun teh hitam dari berbagai sampel dengan konsentrasi yang digunakan 8, 16,24, 32,dan40µg/ml. Analisis data untuk mengetahui kadar tanin dengan menggunakan metode kurva standar, regresi linier y = a + bx. Hasil yang diperoleh dari uji kualitatif KLT terdapat bercak noda sampel dan pembanding pada UV 254 nm, yaitu Rf T1 sebesar 0,84 cm , T2,T4,T5,T8, T9 sebesar 0,85 cm, pada sampel T3,T7,T10,T11 diperoleh nilai Rf sebesar 0,86 cm yang nilai Rf nya sama dengan pembanding katekin. dan pada sampel T6 diperoleh nilai Rf sebesar 0,81 cm. Adapun untuk uji kuantitatif nya diperoleh kadar tertinggi pada sampel T1, T3, T6, T8, T10 sebanyak 0,004 ± 0 g/g sedangkan kadar terendah diperoleh sampel T2, T4, T5, T7, T9, T11 sebanyak 0,003 ± 0 g/g, Hal ini dapat disimpulkan bahwa tanin yang beredar produksi Pekalongan memenuhi syarat batas konsumsi.Kata kunci: Kadar; Teh; Tanin; Spektrofometri UV-Vis

A cucurbit[7]uril-based supramolecular fluorescent probe for the detection of metronidazole with high sensitivity and strong anti-interference capacity

We propose a new method for the selective detection of the antibiotic metronidazole (MNZ) using CB[7]-JAT (cucurbit[7]uril = CB[7] and JAT = jatrorrhizine) as a fluorescent probe, which is based on the competitive reaction between MNZ and JAT for the occupancy of the CB[7] cavity. The proposed method gives a good calibration curve in the concentration range of 0.38–60 μM, and the limit of detection for MNZ is 65 ng mL−1 with those obtained by the standard curve method. Moreover, the proposed method was successfully applied for the determination of MNZ in liquid milk. Most importantly, due to the high binding affinity between CB[7] and MNZ, the proposed method shows great anti-interference capacity to accurately detect MNZ in the presence of other antibiotics.

Impact of Amplification Efficiency Approaches on Telomere Length Measurement via Quantitative-Polymerase Chain Reaction

Background: Precise determination of amplification efficiency is critical for reliable conversion of within-sample changes in fluorescence occurring on a logarithmic scale to between-sample differences in DNA content occurring on a linear scale. This endeavor is especially challenging for the telomere length (TL) quantitative-PCR (qPCR) assay, where amplification efficiency can vary between reactions targeting telomeric repeats (T) and those targeting a single-copy gene (S) to calculate TL as the T/S ratio.Methods: We compared seven different approaches toward estimating amplification efficiency, including the standard-curve method utilized by the qPCR instrument software, and alternative approaches which estimate efficiency on a reaction-by-reaction basis using the stand-alone program LinRegPCR. After calculating T/S ratios using efficiency estimates from each approach (N = 363), we tested their relative performance on metrics of assay precision and correlates of external validity including chronological age (age range = 1–72 years), across tissues within-person (leukocyte-buccal), and between parents and offspring.Results: Estimated amplification efficiency for telomere reactions was significantly lower than estimates for single-copy gene reactions. Efficiency estimates for both reaction sets were significantly higher when estimated with the standard-curve method utilized by the qPCR instrument relative to estimates reconstructed during the log-linear phase with LinRegPCR. While estimates of single-copy gene efficiency reconstructed using LinRegPCR measured within 90% of perfect exponential doubling (E = 1.92), estimates generated using the standard-curve method were inflated beyond 100% (E = 2.10–2.12), indicating poor fidelity. Despite differences in raw value, TL measurements calculated with LinRegPCR efficiency estimates exhibited similar relationships with external validity correlates to measurements generated using the qPCR instrument software.Conclusion: Since methods to estimate amplification efficiency can vary across qPCR instruments, we suggest that future analyses empirically consider external methods of efficiency calculations such as LinRegPCR, and that already generated data be re-analyzed to glean possible improvements.

Characterization of the Key Aroma Compounds in the Fruit of Litsea pungens Hemsl. (LPH) by GC-MS/O, OAV, and Sensory Techniques

The key aroma compounds in the fruit of Litsea pungens Hemsl. (LPH) were concentrated through solvent-assisted flavor evaporation (SAFE) and characterized by gas chromatography-mass spectrometry-olfactometry (GC-MS/O), quantitative descriptive analysis (QDA), odor activity values (OAVs), and addition test. The results showed that LPH contained 31 aroma-active compounds (flavor dilution, FD = 9). Among them, 30 odorants were quantified by the standard curve method. The OAV analysis results showed that 25 odorants had OAVs ≥ 1, which could be considered as the potent odorants. D-Limonene and 3,7-dimethyl-2,6-octadienal had the highest OAVs (OAV = 9803 and 8399), followed by (Z)-3,7-dimethylocta-2,6-dienal (OAV = 1893), β-myrcene (OAV = 1798), (E)-3-phenyl-2-propenoic acid ethyl (OAV = 1603), and β-caryophyllene (OAV = 1129). Addition experiments further confirmed that 3,7-dimethyl-2,6-octadienal, (Z)-3,7-dimethylocta-2,6-dienal, and D-limonene contributed to lemon attribute, β-myrcene contributed to green attribute, citronellal contributed to mint and fresh note, and eucalyptol contributed to eucalyptus-like note were the key odorants.

A Comparative Analysis of Methods for Titering Reovirus

Background: A key challenge in the process of virus amplification is the need for a simple and convenient method for measuring virus titers. Objective: Real-time unlabeled cell analysis (RTCA) was used to establish a standard curve of correlation between half-cell index time (CIT50) and virus titer. At the same time, the virus titer from tunable resistance pulse detection (TRPS) technology was compared with the traditional median tissue culture infectious dose (TCID50) method to evaluate the feasibility and application value of the RTCA technique and TRPS technology. Methods: : Cell index (CI) values for L929 cells under different culture conditions were detected, and the appropriate initial cell inoculation density was screened. The half-cell index (CI50) values of reovirus infected L929 cells with TCID50 titers were analyzed by RTCA, the CI50-TCID50 standard curve was created, and a regression equation was developed. RTCA, TCID50, and TRPS methods were used to detect the reovirus titer obtained by the amplification, and the sensitivity and feasibility of the CIT50-TCID50 standard curve method were analyzed. The virus titer was detected by TRPS technology and the TCID50 method. Results: L929 cells were best propagated at an initial density of 6 × 103 cells/well. After infecting L929 cells with different titers of reference reovirus, the linear correlation of CIT50 and TCID50 was y = -2.1806x + 71.023 (R2 = 0.9742). The titer resulting from the RTCA assay was 7×109.6821 pfu/mL, from the TRPS assay was 4.52×1010 pfu/mL, and from the TCID50 assay was 7×109.467 pfu/mL. Conclusion: The CIT50-TCID50 standard curve method established by the RTCA technique can be used to quantitatively detect reovirus titer with L929 cells. Compared with the TCID50 method, it takes a relatively short time and has high sensitivity and accuracy. The TRPS technology requires even less time to quantify the virus, but its precision is lower than that of the TCID50 method and RTCA technology. This study provides new technical methods for assessing the virulence of infectious live reovirus particles. Lay Summary: After amplification of the virus, we need to detect the virus titers (the virulence of the virus). The traditional method is to use the virus to infect cells, and then the virus titers can be calculated by 50% of the cells infected. However, this traditional method is time consuming. The ways of RTCA (a real-time cell analysis technique) and TRPS (a nano-bioparticle analysis technique) help us to detect viral titers. The consistency of these three methods determines their feasibility and accuracy. If they are feasible, then these two simple technologies will provide new ideas for detecting viral titers.

Exploring the formaldehyde reactivity of tannins with different molecular weight distributions: bayberry tannins and larch tannins

In recent years, tannin degradation has been used to obtain tannin materials with an optimal molecular weight distribution (MWD) for synthesizing tannin-formaldehyde (TF) resin with high performance, but the optimal MWD of tannins is still unknown. The excellent formaldehyde reactivity of tannins is the basis for the synthesis of high-performance TF resin. Based on the formaldehyde reactivity of tannins, bayberry tannins and larch tannins were used to explore the optimal MWD of tannins for TF resin synthesis. Progressive solvent precipitation (PSP) was used to obtain tannin fractions with different MWDs. The formaldehyde reactivity of tannins was determined using the modified Stiansy method combined with the standard curve method (GB/T 17657-2013). The bayberry tannin fraction [weight-average molecular weight (Mw) of acetylated tannin: 4115, mean degree of polymerization (mDP): 6.64] and the larch tannin fraction (Mw of acetylated tannin: 3906, mDP: 5.84) had the best formaldehyde reactivity. Furthermore, significant differences in the formaldehyde reactivity of condensed tannins (CTs) with different MWDs were observed. The obtained results can be used to purposefully degrade tannins to achieve an optimal MWD, which is beneficial for the production of TF adhesives with high performance.

ANALYSIS OF TOTAL PHENOLIC FROM A ROOT TABAR KEDAYAN

East Kalimantan has a diversity of plants from various Dayak ethnic groups. One of them is the Tabar Kedayan (Aristolochia foveolata Merr) plant located in Malinau district. This plant is empirically efficacious as antidiarrhea, antidotum (anti poison). Efficacy of Tabar Kedayan plant has not been scientifically confirmed, this is because there is still little scientific research and information about the content of secondary metabolites and bioactive compounds contained in Tabar Kedayan Root. The presence of secondary metabolite is phenolic which has considerable biological active prospects as antioxidant, antibacterial, antiamuba, anti-inflammatory, antihepatotoxic and antivirus. The aim of this research is to analyze the chemical content and total phenolic content of root tabar kedayan in fractionation with various nonpolar, semipolar and polar solvents. The analysis used in the determination of total phenolic content using visible spectrophotometric method. Data of analysis used standard curve method based on absorbance data and concentration of standard solution. The results of this study obtained the highest total phenolic average on ethyl acetate fraction of 77.74 ±2,633 mg GAE/g then ethanol fraction of water amounted to 38.10 ±0,461 mg GAE/g and the smallest level of n-hexane fraction of 29.36±0,193 mg GAE/g. Conclusions in this study total phenolic content is found in most semipolar fractions.

Ultra violet spectrophotometric analysis of Paracetamol, Diclofenac and Tramadol drugs in mixture

The aim of this research was develop and validate an analytical method by Uv spectrophotometric technique for quantitative determination of paracetamol (PAR), diclofenac or voltarine (DIC) and tramadol or tramal (TRA) in tablet dosage form, paracetamol analysis is based on the absorbance maxima were found to be at 243 nm when dissolved in 0.1N H2SO4 as a sample and in 0.1N NaOH solution as a blank,. Quantitative of PAR in sample is achieved by standard addition methods and three ways calculations were used to estimate the amount in the tablet, the expected content per tablet were equal to (365.60, 361.984, 358.415 mg) and the results were acceptable when compared with original quantity in tablet(350 mg). The method was compared with standard curved method, showed that it is obeyed Beer – lambert law in the concentration range of 0.1–1 µg/ml for standard addition and standard curve methods, with a correlation coefficient of 0.9980 and o.9944. The limit of detection (LOD) for PAR was 0.036 µg/ml while limit of quantitation (LOQ) 0.119 µg/ml, the recovery of three procedure A, B, C of standard addition and standard curve were (104.40, 103.42, 102.40 and 92.995 %) for PAR ,it was found that the results obtained from the standard addition method were better than the result obtained from the standard curve method. The amount of (DIC) and (TRA) drug in tablet sample calculated depending on the absorbance (A) at 273 nm to give the value 47.44 mg and 47.6 mg per tablet are acceptable when compared with the value of the original quantity in tablet (50mg) and the recovery of the method was found to be (95.2 and 96.0 % ) respectively, the principle of the method based on the (A) of mixture at this λ is a total A of the two drugs, which owns different intensity at this λ at different percentages and that apply to the sample and standard for this drugs. Finally this can applied successfully for routine analysis. http://dx.doi.org/10.25130/tjps.24.2019.047

Determination of the Correction Factor for Dinalmefene Hydrochloride in Nalmefene Hydrochloride Injection

Objective: To calculate the detection correction factor for the impurity, that is, the dinalmefene hydrochloride in nalmefene hydrochloride injection. Methods: High performance liquid chromatography (HPLC) is used to analyze the impurities of nalmefene hydrochloride easily produced during storage, and the impurity is determined and correction factor is calculated for the known the dinalmefene hydrochloride. According to the standard curve method, the sample concentration is selected between the detection limit and the limit of quantification, and the standard curve is prepared. The correction factor is then calculated according to the slope of the standard curve. Results: finally, the correction factor for dinalmefene hydrochloride is 0.22. Conclusions: the correction factor calculated by the standard curve method is accurate and reliable, and can be used for impurity detection of nalmefene hydrochloride injection.

Discrimination and Simultaneous Determination of 6-BA and KT by Polarized Synchronous Light Scattering and Synchronous Light Scattering Spectrum

In pH=5.70 B-R buffer solution, Na2WO4 and rhodamine 6G（R6G） could react with natural cytokinins of 6-benzylaminourine (6-BA) and kinetin (KT) and resulted in a great enhacement of synchronous light scattering (SLS) signals. This article first established the degree of polarized synchronous light scattering (P) based on the measurements of the polarized synchronous light scattering signals to distinguish two natural cytokinins of 6-BA and KT. Simultaneously based on the synchronous scattering spectrum and the double standard curve method, a novel method for simultaneous determination of 6-BA and KT was developed by SLS spectralmethod. The method was applied to simultaneous determination of 6-BA and KT in balsam pear skin and tomato skin with satisfactory results.