Iodine Titration Method Research Articles

An isocratic HPLC-UV analytical procedure for assessment of glutathione and its related substances

Reduced glutathione (GSH) is an endogenous tripeptide antioxidant which plays a crucial role in a variety of physiological and pathological activities. Although GSH is not present in any FDA-approved drug product, GSH dietary supplement products and compounded GSH drugs are available to patients in the US. Several incidents of toxicity have occurred in recent years due to endotoxin or otherwise contaminated GSH in compounded drugs. Efficient and sensitive analytical methods are needed for assessing and ensuring the quality of GSH substance and associated drug or dietary supplement products. Impurities A (L-cysteinylglycine), B (cysteine), C (oxidized L-glutathione) and D (γ-L-glutamyl-L-cysteine) are the main related impurities for GSH drug substance which have been detected and quantified by capillary electrophoresis and qNMR analytical procedures. However, there are no reported HPLC methods for detecting or quantifying the three main related impurities A, B and D even though numerous HPLC analytical methods have been reported for analyzing GSH and impurity C. In this report, an isocratic HPLC-UV analytical procedure was developed and validated for separating and identifying GSH and related impurities A-D as well as a newly identified degradant, L-pyroglutamic acid (pGlu), within 10 minutes with resolution (RS) more than 3. The LOD and LOQ were determined to be 0.02 % w/w and 0.05 % w/w, respectively, for impurities A-D and pGlu. Importantly, the optimized HPLC analytical procedure for GSH assay does not have interference from impurities A, B and D, providing highly specific results compared to the commonly used iodine titration method. The newly validated analytical procedure was applied to assess different commercial GSH bulk substance samples. The results suggest that the analytical procedure described in this work is suitable for quality assessment of GSH samples.

Chemical and Organoleptic Quality of Kombucha Tea at Different Fermentation Time and Concentration of Cherry Leaves (Muntingia calabura L.)

The leaves of the cherry plant (Muntingia calabura L.) contain vitamin C and phenolic compounds. High phenolic compounds have the potential to have antioxidants. Efforts to increase antioxidant activity can be carried out by fermentation using SCOBY. The purpose of this study was to determine the effect of cherry leaf concentration and fermentation time on the chemical and organoleptic quality of cherry leaf kombucha tea, and to determine the best treatment for cherry leaf kombucha tea. This study used a completely randomized design (CRD) which was arranged in a factorial manner with 2 factors. The first factor is the fermentation time with 3 levels (4 days, 8 days, 12 days). The second factor is the concentration of cherry leaves with 3 levels (1%, 2%, 3%). Each treatment combination was repeated 3 times. The chemical analysis of cherry leaf kombucha that will be tested is the total phenol content using the Folin Ciocalteau reagent with the spectrophotometric method, antioxidant activity with the DPPH method, and vitamin C with the iodine titration method. Analysis of organoleptic quality was carried out by testing the level of preference / hedonic test which included color, aroma, and taste. Determination of the best treatment is done by using the effectiveness test. K3L2 treatment with 3% cherry leaf concentration and 8 days of fermentation gave the best treatment results, namely 0.71, which means that this treatment is the best treatment with parameter criteria including antioxidant 109.77 ppm, phenol 9.42 mg GAE/g, vitamin C 22.92 ppm, taste 3.85 (neutral), scent 3.00 (rather dislike), and color 5.00 (rather like)

The Analysis of Glucose and Vitamin C on Papaya (Carica papaya L.) with Different Time Storage

Papaya (Carica papaya L.) contains vitamins, carbohydrates, minerals, fiber, and enzymes that are useful for digestion. Storage after harvest is usually done for trading needs. The length of storage will affect glucose and vitamin C levels contained in it. The purpose of this study was to determine differences in glucose and vitamin C levels with different storage times. The method in this study is descriptive quantitative. Samples of C. papaya L. were obtained from farm farmers in Wayharong village, Waylima sub-district, Pesawaran district. This study consisted of 2 treatments, 3 days and 6 days of storage, each of which was 3 repetitions. Glucose levels were measured using the Luff Schoorl titration method. While the determination of vitamin C levels uses the iodine titration method. The results of the study data were analyzed by one-way ANOVA, followed by the LSD test at 5% level. The results showed differences in storage time with glucose levels increased compared to controls, with the highest increase of 7.23% in the storage period of 6 days. The storage duration also caused an increase in vitamin C levels. The highest storage time of 3 days was 16.88 mL / 100 gr.

Analisis Kandungan Vitamin C dan β-Karoten Lada Katokon Toraja, Cabai Besar dan Cabai Keriting di Makassar

Chili is one of the spices that are consumed by many Indonesians. It has several vitamins, one of which isvitamin C and ß-carotene is a pro-vitamin A which plays an important role in the formation of vitamin A. The studywas conducted in August 2018 and sampling from the regions Toraja and Malino. This study aims to determine thelevels of vitamin C in several types of chilli obtained by using iodine titration method and the levels of ß-caroteneby spectrophotometric method at a wavelength of 460-480 nm. The chili sample was first measuredmorphologically, weighed by base and dry weight and its water content. The test results showed vitamin C levels ofPepper Katokon Toraja Capsicum annuum L. Var. Sinensis is tested with seeds (0.129% / 10 g) and seedless(0.182% / 10 g). Large Chili Capsicum annuum L. Var. Abreviatum Fingerhuth was tested with seeds (0.220% / 10g) and seedless (0.223% / 10 g). Curly Chili Capsicum annuum L. Var. Longum sendt was tested with seeds(0.537% / 10 g) and seedless (0.592% / 10 g). Test results showed the levels of β-carotene Pepper Katokon TorajaCapsicum annuum L. Var. sinensis were tested with seeds (5.888mg / kg) and seedless (6.073mg / kg). Large ChiliCapsicum annuum L. Var. Abreviatum Fingerhuth was tested with seeds (5.529mg / kg) and seedless (6.338mg /kg). Curly Chili Capsicum annuum L. Var. Longum sendt was tested with seeds (6.655mg / kg) and seedless(6.942mg / kg). Conclusion The highest content of vitamin C and ß-carotene was found in Curly Chili Capsicumannuum L. Var. Longum sendt without seeds.

Determination of Flavonoid, Tannin and Vitamin C Content from Methanol Extract Wrapping Stone Banana (Musa brachycarpa), Ketip Banana (Musa Paradisiaca Forma Typiaca) and Kepok Banana (Musa acuminata)

Research has been done to investigate the levels of flavanoid, tannin, and vitamin C of methanol extract of Stone banana (Musa brachycarpa), Ketip banana (Musa paradisiaca forma typiaca ), and Kepok banana (Musa acuminata). Jukut Ares is a Balinese traditional cuisine frequently served in any events of celebrations. The use of young stems of such banana varieties as the main raw materials in the process of making jukut ares has not been scientifically elucidated. Antioxidants are compounds with ability to inhibit oxidation-related reactions due to free radicals that cause disturbance of saturated fatty acids of cell membrane, blood vessels, DNA, as well as adipose tissues which lead to occurrence of various diseases. Plants components will have antioxidant activities if they contain compounds (phenol and flavanoid) with ability to scavenge free radicals. Tannin is a water based phenolic compound and vitamin C is also a water based vitamin that play important roles in preventing us from various diseases. Extraction was conducted by applying maceration method and to investigate the levels of flavanoid, spectrophotometric UV vis with aluminum chloride (AlCl3) was applied. The level of vitamin C of the materials was conducted by Iodine titration method, while the level of tannin was determind by applying spectrophotometri. The results showed that methanol extract of Ketip banana stem contained the highest level of flavanoid with a quantity of 53.13 mg/100gr QE, and this was followed by stone banana (36.28) and kepok banana (32.07) The highest vitamin C level was indicated in the extract of ketip banana (418.32 mg/100gr), which is followed by kapok banana and stone banana. In the calculation of tannin content, pisang ketip showed the highest level, while pisang batu contained the lowest level of tannin.

Design and preparation of cross‐linked α‐methylstyrene acrylonitrile copolymer nanoparticles and their interfacial investigation with rubber

ABSTRACTCross‐linked α‐methylstyrene and acrylonitrile (MStAN) copolymer particles in a latex form were synthesized by free radical emulsion polymerization. The particles showed a narrow size distribution and an average diameter of 65 nm. The amount of the vinyl groups at the surface of the (MStAN) copolymer particles resulted from varied amount of the initiator (APS) and the cross‐linking agent (DVB) was detected by iodine titration method. When filled into ethylene propylene rubber (EPR), the MStAN nano‐particles exhibited excellent reinforcing capabilities, and with the increase of the vinyl groups at the surface of MStAN particles, the tensile stress of MStAN/EPR increased. Results demonstrated that the vinyl groups at the surface of the (MStAN) copolymer particles provided certain chemical interactions between the filler particles and the macromolecular chains of rubber matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41914.

A Comparative Study of the Antioxidant Properties of Three Pineapple (Ananas comosus L.) Varieties

The objective of this study was to determine the antioxidant activity of different pineapple varieties namely Josephine ( Ananas comosus L. var. comosus cv. Josephine), Morris ( Ananas comosus L. var. comosus cv. Morris), and Sarawak ( Ananas comosus L. var. comosus cv. Sarawak). Different concentrations of methanol, ethanol, and acetone were used to extract the phenolic compounds. Folin Ciocalteu’s reagent was used to determine the total phenolic content. The ascorbic acid content of the fruit extracts was determined using the iodine titration method. The antioxidant activity of the pineapples was measured using the 2,2-diphenyl-1-picryhydrzyl (DPPH) radical scavenging assay, the Ferric Reducing Power (FRP) assay and the Ferrous Ion Chelating (FIC) assay. 50% methanol was chosen as the best solvent for extracting the phenolic compounds of the pineapples. Morris pineapple was found to contain the highest TPC (53.8±0.7 mg GAE/100g fruits) and antioxidant activity. This variety was also found to have the highest DPPH scavenging activity (25.2±0.5 mg AA/100g fruits), FRP (29.6 mg GAE/100g fruits) and FIC ability (8%/100g fruits). Despite having a higher TPC than the Sarawak variety, Josephine exhibited a low scavenging activity. Strong positive correlations (R 2 = 0.9943) were observed between the ascorbic acid content and scavenging activity, as well as between TPC and FRP (R 2 = 0.9475). Only a weak correlation (R 2 = 0.158) was observed between corrected TPC and FRP. FIC ability was observed in all the extracts.

Quantitative evaluation of vitamin C in industrial lemon juice by titration method

One of the most important micronutrients of lemon juice is vitamin C. Vitamin C is a sensitive antioxidant and heat, light and oxygen are included important factors to reduce the amount of this vitamin. This study designed to evaluate vitamin C in in- dustrial lemon juice quantitatively. The present cross- sectional study was conducted on 50 bottles of different types of Shi- raz industrial lemon juice. Vitamin C levels were measured through iodine titration method. Each measurement was repeat- ed 2 times. Then Data were statistically analyzed by using SPSS software. The vitamin C of samples has been reported 18.92±6.66 (mg/100ml). Maximum and minimum vitamin C were 6.01 and 34.08 (mg/100ml) respectively. By using inde- pendent sample t-test, a comparison of the mean vitamin C of industrial lemon juice and The mean vitamin C of fresh lemon (42 mg/100ml) shown that vitamin C of industrial lemon juice is less than fresh lemon, significantly (P<0.05). By applying lin- ear regression test determined that a significant relationship exists between the amount of vitamin C in the lemon juice and duration of post-production (p-value = 0.021). This study showed that content of vitamin C in industrial lemon juice was low- er than the mean value of vitamin C in fresh lemon juice significantly and the amount of vitamin C in the lemon juice and the period after production is a significant association and with increased storage time, the amount of vitamin C reduced.

Evaluation of Antioxidant Properties and Mineral Composition of Purslane (Portulaca oleracea L.) at Different Growth Stages

The main objective of this research was to appraise the changes in mineral content and antioxidant attributes of Portulaca oleracea over different growth stages. The antioxidant activity was measured using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric-reducing antioxidant power (FRAP) assays. The iodine titration method was used to determine the ascorbic acid content (AAC). DPPH scavenging (IC50) capacity ranged from 1.30 ± 0.04 to 1.71 ± 0.04 mg/mL, while the ascorbic acid equivalent antioxidant activity (AEAC) values were 229.5 ± 7.9 to 319.3 ± 8.7 mg AA/100 g, total phenol content (TPC) varied from 174.5 ± 8.5 to 348.5 ± 7.9 mg GAE/100 g. AAC 60.5 ± 2.1 to 86.5 ± 3.9 mg/100 g and FRAP 1.8 ± 0.1 to 4.3 ± 0.1 mg GAE/g. There was good correlation between the results of TPC and AEAC, and between IC50 and FRAP assays (r2 > 0.9). The concentrations of Ca, Mg, K, Fe and Zn increased with plant maturity. Calcium (Ca) was negatively correlated with sodium (Na) and chloride (Cl), but positively correlated with magnesium (Mg), potassium (K), iron (Fe) and zinc (Zn). Portulaca olerecea cultivars could be used as a source of minerals and antioxidants, especially for functional food and nutraceutical applications.

Defect structure and electrical properties of LaSr 3Fe 3O 10–δ

As a mixed conductor, LaSr 3Fe 3O 10–δ with triple layer perovskite intergrowth structure can be used as an oxygen separation membrane material and cathode material in solid oxide fuell cells. LaSr 3Fe 3O 10–δ was synthesized via citrate acid route. Iodine titration method was used to determine the average valence of transition metal Fe and oxygen nonstoichiometry δ. Conductivities of LaSr 3Fe 3O 10– δ were measured in the oxygen partial pressure range from 10 −2 × 10 5 to 1 × 10 5 Pa, by Ac four probe method. Seebeck coefficient measurement together with conductivity results indicated that LaSr 3Fe 3O 10– δ is a p-type conductor. A linear relationship between the conductivity and logarithm of oxygen partial pressure was observed in the measurement. A defect model was introduced to explain the observed phenomena in the iodine titration, conductivity and Seebeck coefficient measurement. Electrical conductivity relaxation method was used to determine the oxygen chemical diffusion coefficient D chem. The apparent activation energy of oxygen chemical diffusion was calculated to be 61.4 kJ/mol.

Antioxidant properties of different cultivars of Portulaca oleracea

Methanolic extracts of six cultivars of Portulaca oleracea were analyzed for their total phenol content (TPC) using the Folin–Ciocalteu method. The antioxidant activity was measured using the 1,1-diphenyl-2-picrylhydrazyl, ferric-reducing antioxidant power (FRAP) and β-carotene bleaching (BCB) assays. The iodine titration method was used to determine the ascorbic acid content (AAC). The TPC of the cultivars of P. oleracea ranged from 127 ± 13 to 478 ± 45 mg GAE/100 g of fresh weight of plant. There was good correlation between the TPC value and its AEAC, IC 50 and FRAP values ( r 2 > 0.9) for all the cultivars. The AAC for the cultivars ranged from 38.5 ± 0.6 to 73.0 ± 17.5 mg/100 g. The TPC value of the common variety PO1, was the lowest compared to the ornamental cultivars (PO2–PO6). The BCB assay showed that all cultivars were capable of inhibiting lipid peroxidation and the inhibition power did not correlate with TPC value.

An investigation of silicon-doped LiCoO 2 as cathode in lithium-ion secondary batteries

Powders of layered–structured LiCo (1− x) Si x O 2 ( x = 0, 0.01, 0.05, 0.10, 0.35) were synthesized by a co-precipitation method followed by a 950 °C sintering. Their structures were analyzed by the X-ray diffraction (XRD) and scanning electron microscopy (SEM). Iodine titration method was also employed to measure the average valence of cobalt ions. With these powders as the active materials of positive electrodes versus lithium, the electrochemical behaviors of the cells were investigated using charge–discharge cycling, AC impedance spectroscopy and DC resistance measurement. It is found that the Si-doping results in the decrease of cobalt valence and the crystallite size. When the Si-content is less than 10%, pure LiCo 1− x Si x O 2 phases are obtained. A second phase Li 2CoSiO 4 is also obtained when the Si-content is 35%. Among the five compositions, the non-doped LiCoO 2 exhibits a high initial specific capacity (about 150 and 185 mA h/g at a current density of 0.4 mA/cm 2 from 2.8 to 4.2 and from 2.8 to 4.5 V, respectively), but degrades in the following cycles; while the Si-doped LiCo 1− x Si x O 2 electrodes especially LiCo 0.99Si 0.01O 2 show the best performance of long-life cycling. And all of the doped powders have better stability of the 3.6 V-plateau efficiency due to the improved stability effect on the cell impedance.

The release of vitamin C from chewing gum and its effects on supragingival calculus formation

The aims of this study were to evaluate (i): whether vitamin C in chewing gum, alone or in combination with carbamide, influences calculus formation, and (ii) whether carbamide affects the release, stability and uptake of vitamin C in a chewing gum. In two test series (Series I and II), 30 subjects, all calculus formers, participated. They were instructed to chew on five (Series I) or 10 (Series II) pieces of gum per day for a period of 3 months. The chewing gums were: vitamin C (60 mg, Series I), non-vitamin C (Series I) and vitamin C + carbamide (30 mg + 30 mg, Series II). In both series, no gum was used as a negative control. Calculus formation was scored on three lingual sites on the six anterior mandibular teeth according to the Volpe-Manhold index. The effect on plaque and gingivitis was also determined. A significant reduction in the total calculus score was observed after the use of vitamin C (33%) and vitamin C + carbamide (12%) gums compared with no gum use; this reduction was most pronounced in the heavy calculus formers. A reduced amount of visible plaque was also observed after use of vitamin C and non-vitamin C gum, but only the vitamin C gum reduced the number of bleeding sites (37%). In a separate study, the release, stability and uptake of vitamin C were evaluated using the iodine titration method in both saliva and urine after exposure to the following gums: vitamin C + carbamide (30 mg + 30 mg) and vitamin C (30 mg). There was no indication that carbamide affected the release, stability or uptake of vitamin C when used in a chewing gum.

熱帯産澱粉のアミロペクチンの鎖長分布について

The distribution of a-1, 4 chains in amylopectins from 4 kinds of tropical starches, i. e., from edible canna, arrowroot, cassava and sago, were examined. Potato and corn starches were used as controls. Each starch was debranched with isoamylase and then chromatographed on a Sephadex G-75 column. The eluates were fractionated into 3 peaks by measuring the reducing and total sugars and the iodine color reaction. Fraction I is thought to have been derived from amylose, and the content of fraction I agreed with the content of amylose by the amperometric iodine titration method except edible canna and corn starches. Fractions U and IQ are thought to have been derived from the long and short chains of amylopectin, and the average chain lengths of the combined II and Ilt fraction of potato and edible canna starches were approximately 18, while the values for the other four starches were approximately 16. The weight% values of fraction II of the potato and edible canna starches were 38.1 and 35.1%, respectively, and the mol% values were 16.2 and 14.8%. The weight% values of fraction II of the other four starches were 23.6-27.9% and the mol% values were 9.1-11.1% (refer to Table 2). These results show that potato and edible canna starches have more long chain branches than the other four starches. It is also shown that the edible canna, sago and corn starches were rich in branches, the chain length of which was longer than 10 and shorter than 20. In contrast, the potato and arrowroot starches were rich in short chains, with a chain length shorter than 10. The potato and edible canna starches showed X-ray diffraction patterns of the B type, while cassava, arrowroot, and corn starches were of A type, and sago starch of C type close to A. The relationship between the crystalline type and the average chain length of the amylopectins showed the tendency for the A type to have a shorter chain length than the B type.

ポーラログラフィーによる油脂過酸化物価の測定

Peroxide value (POV) of the oils at low oxidation levels is difficult to be determined by the standard iodine titration method. Hydroperoxides of triglycerides showed a polarographic wave at -0.6 V. The POV of highly oxidized oil was easily determined by iodine titration method. Such a highly oxidized oil was diluted with benzene and was used as the standard solution for determining a polarographic calibration curve. The wave height was proportional to hydroperoxide concentration. The POV of an uncharacterized sample was obtained by reading the wave height on the calibration curve. This simplified polarographic method is considered to be useful for the determination of POV at low levels of lipid oxidation.

Der Verlauf des Stärkeabbaues bei der Mälzung und während des Maischens in der Bierbrauerei

AbstractThe Course of Starch Degradation During Malting and Mashing in the Brewery. The photometric iodine titration method was successfully applied to examine starch degradation during malting and mashing in the brewery. By this method the apparent degree of degradation as well as the changes in heterodispersity corresponding to the respective molecular weight of the starch were determined. During germination of the barley heterodispersity of starch changes but slightly. Starch degradation takes place mainly during the preparation of the malt mash. In the final part of the amylolytic period only a small amount of non degraded starch remains in the draff. During enzymatic mashing the characteristic values of the malt mash are not reached till in the last periods of the mashing process. Total degradation takes place only after swelling and gelatinization. This can be attributed to the different effect of the added α‐amylase preparation.

Determination of polyvinylpyrrolidone by an lodine titration method

A new method, partly based on a procedure originally suggested by Cannan (2), for the analytical determination of PVP in serum and urine samples has been developed. Creatinine in urine does not interfere. Materials, such as proteins in serum, which do interfere, are first precipitated out by addition of ethyl alcohol. An iodine solution is then added to the clear alcoholic solution; the iodine precipitates out a PVP-I 2 complex which is separated by centrifugation, washed, dissolved in a suitable solvent such as methyl Cellosolve, and titrated with standard thiosulfate. The advantage of this method is that, by proper calibration, good results (usually within ±6% and almost always within 10%) over a very wide range of PVP concentrations (1 to 150 mg PVP/ml) can be obtained on the original sample without rerunning the analysis at other sample dilutions. A more detailed account of the development work on the iodine titration method is to be found in a report to the Office of Naval Research (5).

Effect of Pancreatectomy on Glutathione Content of Blood

Complete pancreatectomy in the dog causes an increase of over 100% in the non-glucose reducing substance of venous blood. (Table.) This substance is determined quantitatively by the iodine titration method of King et al. for blood glutathione as modified by Mancorps and Schmid. At this stage of the research we assume this substance to be glutathione; however, the method employed is not specific but may include such substances as thioneine and cystein. Ascorbic acid also interferes with this titration. The above mentioned interfering substances are probably not present in quantities sufficiently great to cause appreciable error in our interpretations. Further work on this phase is in progress. Section of the splanchnics in the dog causes a decrease of approximately 50% in the blood glutathione, but no effect on the experimental diabetes following pancreatectomy. Acetone given by mouth in dosages of 6 ce. per kilo of body weight causes this gluta-thione-like substance to increase approximately 200% above normal and does not return to normal for approximately 3 days. Removal of the pancreas on the blood glutathione has been studied by Dott D. Ferrari. Our results are at variance with his findings. Blood glutathione determinations before pancreatectomy in his dogs are not published.