Development and certification of reference standards for phenolic content in biologicals, based on comparison of results obtained by GLC, HPLC, spectrophotometric, and colorimetric methods

Phenol is used as a preservative in a number of biological products. Methods that are used for quantitative determination of phenol differ a lot. Current requirements for accredited laboratories include continuous internal quality control. Reference standards with a certified content of the analyte are an effective metrological tool for ensuring such control. The aim of the study was to develop and certify reference standards for phenolic content in biological products, based on comparison of results obtained by GLC, HPLC, spectrophotometric, and colorimetric methods. Materials and methods: diluent for allergens by (candidate reference standard), 2.5 and 5 mg/mL phenol solutions, and 2.5 mg/mL 2-phenoxyethanol solution were used in the study. The experiments were performed using spectrophotometric, colorimetric, HPLC, and GLC procedures. The statistical analysis of results included calculation of the arithmetic mean, standard deviation, coefficient of variation, and analysis of variance with Student’s t-test and Fisher’s F-test. Results: the results of phenolic content determination by the spectrophotometric, colorimetric, and HPLC methods were statistically comparable. The F value obtained for equal sample sizes (n = 40) was F = 0.9343, given the critical value Fcrit = 3.96. A reference standard certified by one of these methods can be used to control the consistency of phenol determination by a relevant method. The results of phenolic content determination by the GLC method showed statistically significantly differences: F = 17.47, given Fcrit = 3.96, which demonstrated the need for certification of another reference standard. Conclusions: two reference standards were certified in the study: reference standard 42-28-449 with the certified phenolic content of 2.56‒3.32 mg/mL, to be used with the spectrophotometric, colorimetric, and HPLC methods; and reference standard 42-28-451 with the certified phenolic content of 2.92‒3.28 mg/mL, to be used with the GLC method.

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Assessment of Protein Quality Methodology for Infant Formulas

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/68.4.680 ◽

1985 ◽

Vol 68 (4) ◽

pp. 680-683

Author(s):

Geraldine Vaughan Mitchell ◽

Mamie Young Jenkins

Keyword(s):

Quality Evaluation ◽

Protein Quality ◽

Reference Standards ◽

Infant Formulas ◽

Casein Diet ◽

Reference Standard ◽

Powdered Milk ◽

The Third ◽

Net Protein

Abstract Rat bioassay was used to assess the protein quality of powdered infant formulas and to evaluate the feasibility of using modified casein diets (containing the same source and level of fat and carbohydrate contributed by the infant formulas) as reference standards. Modification of the casein diet to match the milk-based formulas caused a significant reduction in weekly protein efficiency ratios (PER) and net protein ratios (NPR) at the third and fourth weeks. Modification of the casein diet to simulate the soy-based formulas had no significant effect on NPR values; PER values were more varied. When PER and NPR values of the powdered milk-based formulas were expressed relative to the unmodified reference standard, the relative values were lower than when each matched reference was used. With few exceptions, the relative weekly PER values of the soy-based formulas were similar regardless of the standard used. The relative NPR values of the formulas had a pattern similar to the relative PER values. The data indicate that protein quality evaluation of infant formulas using rat bioassay warrants the use of matched casein reference diets for each type of formula.

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Antioxidant Activities and HPLC-DAD Based Phenolic Content Determination of Bauhinia scandens

British Journal of Pharmaceutical Research ◽

10.9734/bjpr/2016/31817 ◽

2016 ◽

Vol 14 (6) ◽

pp. 1-9

Author(s):

Md Hossain ◽

Sarzil Niloy ◽

Afroza Hosen ◽

Md Islam ◽

Zahirul Islam ◽

...

Keyword(s):

Phenolic Content ◽

Antioxidant Activities ◽

Content Determination

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Chinese Preschool Children Growth Reference Standard and Related Curve: Based on GAMLSS Approach

Iranian Journal of Public Health ◽

10.18502/ijph.v50i6.6424 ◽

2021 ◽

Author(s):

Sanhua Zhang ◽

Chongmin Jiang ◽

Chunjing Tu

Keyword(s):

Preschool Children ◽

Growth And Development ◽

Reference Standards ◽

Chest Circumference ◽

Reference Standard ◽

Sitting Height ◽

Growth Reference ◽

Percentile Curve ◽

And Control ◽

Height For Age

Background: The current national growth and development standard of preschool children in China was formulated in 2003, which has many deficiencies. It is necessary to construct more scientific percentile curve and growth reference standards in order to evaluate more effectively the growth, development and health status of Chinese children. Methods: Based on the physical and health data of 31 provinces in China measured in 2010 and 2014, the GAMLSS model was used to construct the growth reference standard and correlation curve. Results: We obtained growth reference standards for percentile curve and Z-score curve of height-for-age, sitting height-for-age, Weight-for-age, Chest circumference-for-age of Chinese preschool children. The C50 percentile of all indicators showed an obvious increasing trend with aged 3.0 to 6.5. Such as, the height of boys and girls increased by 21.1cm and 20.3cm respectively, the sitting height boys and girls increased by 10.3cm and 10.1cm respectively, the weight of boys and girls increased by 7.1 kg and 6.3 kg respectively, the Chest circumference of boys and girls increased by 6cm and 5.2 cm respectively. Conclusion: The children's growth and development charts provided in this study provide effective monitoring and personalized evaluation tools for the growth and development assessment of preschool children, as well as for the reduction of malnutrition, prevention and control of childhood obesity. It is recommended to be used in some areas such as child health, medical treatment and public health.

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Exploration, phenolic content determination, and antioxidant activity of dominant pteridophytes in Gunung Malang Village, Mount Halimun Salak National Park, Indonesia

Biodiversitas Journal of Biological Diversity ◽

10.13057/biodiv/d210834 ◽

2020 ◽

Vol 21 (8) ◽

Author(s):

RINDITA RINDITA ◽

Vivi Anggia ◽

EKA RAHMAESA ◽

RETNA KUSUMA DEVI ◽

LIDIA FATMAH ALAWIYAH

Keyword(s):

Antioxidant Activity ◽

National Park ◽

Phenolic Content ◽

Abiotic Factors ◽

Ultrasonic Method ◽

Total Phenolic ◽

Phytochemical Screening ◽

Ecological Requirements ◽

Content Determination ◽

Closed Canopy

Abstract. Rindita, Anggia V, Rahmaesa E, Devi RK, Alawiyah LF. 2020. Exploration, phenolic content determination, and antioxidant activity of dominant pteridophytes in Gunung Malang Village, Mount Halimun Salak National Park, Indonesia. Biodiversitas 21: 3676-3682. Pteridophytes have been known to have pharmacological activities as an antioxidant, anti-inflammation, antimicrobials, and anticancer, such as Selaginella sp. In this research, exploration was conducted in Gunung Malang Village, Mount Halimun Salak National Park (TNGHS), West Java. Samples were collected by purposive sampling method, related to its abundant populations, Histiopteris incisa, Nephrolepis biserrata, and Selaginella willdenowii were collected based on different height and light intensity. Abiotic factors were measured to know their ecological requirements. Samples were extracted using ultrasonic method. Organoleptic test, yield, and phytochemical screening were done for the crudes extract. Total phenolic level was determined with Folin-Ciocalteu method and antioxidant activity test with DPPH. Phytochemical screening showed that H. incisa contains phenolics, saponins, tannins, and steroids; N. biserrata contains phenolics, flavonoids, and saponins while S. willdenowii contains phenolics, alkaloids, flavonoids, saponins, and tannins. Phenolic content of H. incisa and N. biserrata from 700 m. asl.was 9.8523 mg GAE/g ± 0.9694 and 17.5399 mg GAE/g ± 0.5350 respectively, from 1000 m. asl. was 18.1231 mgGAE/g ±2.1535 and 8.8468 mg GAE/g ± 0.1437. S. willdenowii extract collected from shaded canopy forest was 19.2324 mg GAE/g ± 0.6041 and opened canopy forest was 38.7087 mg GAE/g ± 1.484. Antioxidant IC50 of H. incisa and N. biserrata from 700 m. asl. respectively was 96.4271 ppm and 85.1907 ppm, while from 1000 m. asl. was 75.6381 ppm and 95.0678 ppm, S. willdenowii from the closed canopy is 101.7326 ppm, while from the opened canopy was 92.0998 ppm. This study shows that all ferns tested gave significant antioxidant activity and was influenced by environmental factors.

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Synthesis and content determination of impurity A of terazosin for use to establish a reference standard for terazosin drug quality control

Pharmaceutical Sciences Asia ◽

10.29090/psa.2018.02.077 ◽

2018 ◽

Vol 45 (2) ◽

pp. 77-92

Author(s):

Do Thi Thanh-Thuy ◽

Xuan Thanh Nguyen ◽

Nam Hai Nguyen ◽

Son Cao Doan

Keyword(s):

Quality Control ◽

Reference Standard ◽

Drug Quality ◽

Content Determination ◽

Drug Quality Control

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Impact of Water Deficit during Fruit Development on Quality and Yield of Young Table Grape Cultivars

Horticulturae ◽

10.3390/horticulturae4040045 ◽

2018 ◽

Vol 4 (4) ◽

pp. 45

Author(s):

Carolin Weiler ◽

Nikolaus Merkt ◽

Simone Graeff-Hönninger

Keyword(s):

Fruit Development ◽

Phenolic Content ◽

Quality Parameters ◽

Table Grape ◽

Soluble Solids ◽

Internal Quality ◽

Total Phenolic ◽

Table Grapes ◽

Yield And Quality ◽

Grape Cultivars

Water limitation has a major effect on agricultural crop production, influencing yield as well as external and internal quality parameters of table grapes. Due to their high yield potential, table grapes have a particularly high risk for yield and quality losses when water is limited, but grapevines are known for high heterogeneity within cultivars. Therefore, we investigated the effect of prolonged water deficits (control, moderate, and severe deficit) during fruit development on yield and quality parameters of four different table grape cultivars (Vitis L.). Furthermore, we ranked their suitability for cultivation in areas suffering from water limitation. Up to 31% of irrigation water could be saved in comparison to the control, without significant negative effects on plant yield, berry size, or internal quality parameters, such as total soluble solids and total phenolic content. However, single bunch yield was highest at a moderate deficit and number of seeds in berries increased with the severity of deficit. Cultivar selection had the greatest influence on water consumption and mainly defined yield and quality parameters. The cultivar ‘Fanny’ produced the highest yields (195.17 g per plant), most bunches per plant (2.04), and biggest berries while cv. ‘Nero’ had the highest total soluble solids content (26.33 °Brix) and the highest total phenolic content (67.53 mg gallic acid equivalents per 100 g fresh weight). Overall, ‘Fanny’ was the most promising cultivar for cultivation under water-limited conditions during fruit development, without significant effects on yield and quality parameters.

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Comparison of GLC and Colorimetric Methods for Determination of Methanol in Alcoholic Beverages

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/54.4.785 ◽

1971 ◽

Vol 54 (4) ◽

pp. 785-786

Author(s):

R H Dyer

Keyword(s):

Colorimetric Method ◽

Alcoholic Beverages ◽

Methanol Content ◽

Comparison Of Results ◽

Colorimetric Methods

Abstract A comparison of results by a proposed GLC method and the present AOAC colorimetric method (9.071-9.074) for methanol in alcoholic beverages is presented. The GLC method utilizes a Carbowax 1500 on Chromosorb W column (similar to 9.063) for determination of methanol content at concentrations as low as 0.003% methanol. In the lower methanol concentrations the GLC results were higher, possibly due to a loss of methanol during the distillation required for the colorimetric method. A total of 20 samples of various alcoholic beverages were analyzed for methanol and the concentration of methanol ranged from 0.004 to 0.37%.

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Chemical and biological assays of Brassica rapa subsp. chinensis (L.) Hanelt

Bangladesh Journal of Botany ◽

10.3329/bjb.v44i2.38525 ◽

2018 ◽

Vol 44 (2) ◽

pp. 327-332

Author(s):

Mohammad S Rahman ◽

Nushrat Jahan ◽

Mahbuba Khatun ◽

Mohammad A Rashid

Keyword(s):

Brassica Rapa ◽

Brine Shrimp ◽

Phenolic Content ◽

Radical Scavenging ◽

Free Radical Scavenging ◽

The Sun ◽

Tropical Zone ◽

Biological Assays ◽

Content Determination ◽

Soluble Fractions

Bangladesh is in the tropical zone blessed with many plants and people of this country are dependent on them to a greater extent for foods and medicines. Brassica is a broad genus and encompasses a lot of herbs. Among these, Brassica rapa subsp. chinensis (L.) Hanelt (Family-Brassicaceae) is famous in Bangladesh as vegetables. In order to explore the healing abilities of B. rapa subsp. chinensis, different chemical and biological assays have been conducted. Initially, the sun-dried powdered herb was extracted well with methanol and then partitioned with petroleum ether, carbon tetrachloride, chloroform and aqueous soluble fractions. All these extractives were subjected to brine shrimp lethality, free radical scavenging, phenolic content determination and antimicrobial assays. B. rapa subsp. chinensis exhibited various responses in the conducted assays depending on the extractives. These studies revealed the facts to consider this plant with medicinal qualities in addition to its general identity as vegetables.

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