scholarly journals FEASIBILITY STUDY ON THE DEVELOPMENT OF REFERENCE MATERIAL OF PESTICIDE IN BLACK TEA

2017 ◽  
Vol 14 (27) ◽  
pp. 146-154
Author(s):  
Dyah STYARINI ◽  
Jarnuzi GUNLAZUARDI
Keyword(s):  
Reference Material ◽  
Feasibility Study ◽  
Mass Fraction ◽  
Dry Weight ◽  
Black Tea ◽  
Weight Basis ◽  
Target Analytes ◽  
Analyte Identification ◽  
Tea Leaf ◽  
Hexane Solution

In this paper, a study on development of reference material (RM) for α-endosulfan and bifenthrin in black tea as a matrix is reported. The study was conducted on the basis that such RMs was presently not available in Indonesia. To obtain a good and proper RM, a feasibility study of RM development is extremely required. The RM was firstly prepared by grinding the tea leaf to have particle size of about 150-106 μm and water content of about 5.99%. A small portion of the grinded tea leaf was then spiked with hexane solution containing both target analytes at certain concentrations, followed by a proper drying to obtain initial candidate of RM (iCRM). The iCRM was then well-mixed properly with another portion of non-spiked grinded tea material to get final candidate reference material (fCRM) powder. A gas chromatography equipped with electron capture detector was used for analyte identification and the feasibility of the method was evaluated in term of spiking technique and homogenization process. The evaluation by ANOVA showed that fCRM was statistically considered to be homogeneous and having α-endosulfan and bifentrin mass fraction ± U of 380.32 (±120.32) ng.g-1 and 522.74 (±148.65) ng.g-1 in dry weight basis, respectively.

ERRORS ASSOCIATED WITH HERBAGE DISSECTION ANALYSES 2. Problems of species identification

1976 ◽  
pp. 213-225
Author(s):  
I.M. Ritchie ◽  
C.C. Boswell ◽  
A.M. Badland
Keyword(s):  
New Zealand ◽  
Dry Weight ◽  
Analytical Tool ◽  
Species Level ◽  
Weight Basis ◽  
Plant Identification ◽  
Leaf Fragment ◽  
Research Division ◽  
Or Groups ◽  
Botanical Analysis

HERBACE DISSECTION is the process in which samples of herbage cut from trials are separated by hand into component species. Heavy reliance is placed on herbage dissection as an analytical tool ,in New Zealand, and in the four botanical analysis laboratories in the Research Division of the Ministry of Agriculture and Fisheries about 20 000 samples are analysed each year. In the laboratory a representative subsample is taken by a rigorous quartering procedure until approximately 400 pieces of herbage remain. Each leaf fragment is then identified to species level or groups of these as appropriate. The fractions are then dried and the composition calculated on a percentage dry weight basis. The accuracy of the analyses of these laboratories has been monitored by a system of interchanging herbage dissection samples between them. From this, the need to separate subsampling errors from problems of plant identification was, appreciated and some of this work is described here.

Polycyclic Aromatic Hydrocarbons (PAHs) in Sediments of the Brisbane River (Australia) – Preliminary Results

1989 ◽  
Vol 21 (2) ◽  
pp. 161-165 ◽  
Author(s):  
S. I. Kayal ◽  
D. W. Connell
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
River Estuary ◽  
Dry Weight ◽  
Weight Basis ◽  
Sediment Samples ◽  
Preliminary Results ◽  
Treated Sewage ◽  
Polycyclic Aromatic ◽  
Petroleum Refineries

Results of the analysis of twenty-three composite sediment samples revealed that PAHs are widely distributed in the Brisbane River estuary. Mean concentrations for individual compounds, on a dry weight basis, ranged from 0.03 µg/g for dibenz [ah] anthracene to 2.34 µg/g for fluoranthene. Observed PAH assemblages were rich in compounds having pyrolytic origins. However, the presence of petroleum derived compounds was indicative of the importance of petroleum as a PAH source in the estuary. Petroleum refineries, a coal loading terminal and a major treated sewage outfall located at the mouth were not indicated as major contributing sources of PAH pollution in the estuary.

Mineral nutrition, dinitrogen fixation, and growth of Alnuscrispa and Alnusglutinosa

1985 ◽  
Vol 15 (5) ◽  
pp. 855-861 ◽  
Author(s):  
G. Prégent ◽  
C. Camiré
Keyword(s):  
Mineral Nutrition ◽  
Dry Weight ◽  
Optimal Growth ◽  
Maximum Growth ◽  
Dinitrogen Fixation ◽  
Weight Basis ◽  
Critical Levels ◽  
N Status

Invitro cultures of Alnuscrispa (Ait.) Pursh and Alnusglutinosa (L.) Gaertn. were used to estimate critical foliage levels of selected nutrients for optimal growth and dinitrogen (N2) fixation. For A. crispa to obtain 90% of maximum growth and N2 fixation, foliar levels of 0.12% P, 0.13% Mg, <0.31% K, and <0.04% Ca on a dry weight basis were needed. For A. glutinosa, the critical levels were 0.138% P, 0.10% Mg, 0.29% Ca, and ~0.20% K. From all the deficiencies observed, P had the more pronounced effects on N status of both species.

scholarly journals Development and certification of a reference material for zearalenone in maize germ oil

2021 ◽  
Author(s):  
Juliane Riedel ◽  
Sebastian Recknagel ◽  
Diana Sassenroth ◽  
Tatjana Mauch ◽  
Sabine Buttler ◽  
...  
Keyword(s):  
Reference Material ◽  
Reference Materials ◽  
Mass Fraction ◽  
High Performance ◽  
Certified Reference Materials ◽  
Maximum Level ◽  
Whole Process ◽  
Commission Regulation ◽  
Maize Oil ◽  
Maize Germ

AbstractZearalenone (ZEN), an estrogenic mycotoxin produced by several species of Fusarium fungi, is a common contaminant of cereal-based food worldwide. Due to frequent occurrences associated with high levels of ZEN, maize oil is a particular source of exposure. Although a European maximum level for ZEN in maize oil exists according to Commission Regulation (EC) No. 1126/2007 along with a newly developed international standard method for analysis, certified reference materials (CRM) are still not available. To overcome this lack, the first CRM for the determination of ZEN in contaminated maize germ oil (ERM®-BC715) was developed in the frame of a European Reference Materials (ERM®) project according to the requirements of ISO Guide 35. The whole process of CRM development including preparation, homogeneity and stability studies, and value assignment is presented. The assignment of the certified mass fraction was based upon an in-house study using high-performance liquid chromatography isotope dilution tandem mass spectrometry. Simultaneously, to support the in-house certification study, an interlaboratory comparison study was conducted with 13 expert laboratories using different analytical methods. The certified mass fraction and expanded uncertainty (k = 2) of ERM®-BC715 (362 ± 22) μg kg−1 ZEN are traceable to the SI. This reference material is intended for analytical quality control and contributes to the improvement of consumer protection and food safety. Graphical abstract

SOLUBLE SUGAR CHANGES OCCURRING DURING COLD HARDENING OF SPRING WHEAT, FALL RYE AND ALFALFA

1983 ◽  
Vol 63 (2) ◽  
pp. 415-420 ◽  
Author(s):  
D. G. GREEN
Keyword(s):  
Spring Wheat ◽  
Soluble Sugar ◽  
Soluble Sugars ◽  
Dry Weight ◽  
Weight Basis ◽  
Cold Hardening ◽  
Spring Type

Alfa, a relatively nonhardy alfalfa cultivar continued to accumulate, on a dry weight basis, fructose, α- and β-D-glucose, sucrose and maltose during the latter stages of cold hardening. Rambler, a hardier alfalfa cultivar conversely showed a decrease for these soluble sugars with hardening. Frontier rye, a very hardy winter habit cereal showed decreases in these soluble sugars plus melibiose during the same hardening period. These results support the hypothesis that hardy cereals and alfalfa undergo a decrease in soluble sugars with hardening, while less hardy cereals and alfalfa continue to increase in content of soluble sugars. Manitou wheat appeared not to fit this hypothesis and showed the decreased soluble sugars usually associated with hardy cultivars. Although Manitou is a spring type wheat, one of its parents, Thatcher, does contain gene(s) for the winter habit.Key words: Sugar, cold hardening, wheat, rye, alfalfa

scholarly journals THE MOLECULAR WEIGHT OF RHODOPSIN AND THE NATURE OF THE RHODOPSIN-DIGITONIN COMPLEX

1954 ◽  
Vol 37 (3) ◽  
pp. 381-399 ◽  
Author(s):  
Ruth Hubbard
Keyword(s):  
Molecular Weight ◽  
Single Molecule ◽  
Extinction Coefficient ◽  
Dry Weight ◽  
Weight Basis ◽  
Sedimentation Behavior ◽  
A Value ◽  
Wet Weight ◽  
Single Boundary ◽  
Stoichiometric Complex

The sedimentation behavior of aqueous solutions of digitonin and of cattle rhodopsin in digitonin has been examined in the ultracentrifuge. In confirmation of earlier work, digitonin was found to sediment as a micelle (D-1) with an s20 of about 6.35 Svedberg units, and containing at least 60 molecules. The rhodopsin solutions sediment as a stoichiometric complex of rhodopsin with digitonin (RD-1) with an s20 of about 9.77 Svedberg units. The s20 of the RD-1 micelle is constant between pH 6.3 and 9.6, and in the presence of excess digitonin. RD-1 travels as a single boundary also in the electrophoresis apparatus at pH 8.5, and on filter paper at pH 8.0. The molecular weight of the RD-1 micelle lies between 260,000 and 290,000. Of this, only about 40,000 gm. are due to rhodopsin; the rest is digitonin (180 to 200 moles). Comparison of the relative concentrations of RD-1 and retinene in solutions of rhodopsin-digitonin shows that RD-1 contains only one retinene equivalent. It can therefore contain only one molecule of rhodopsin with a molecular weight of about 40,000. Cattle rhodopsin therefore contains only one chromophore consisting of a single molecule of retinene. It is likely that frog rhodopsin has a similar molecular weight and also contains only one chromophore per molecule. The molar extinction coefficient of rhodopsin is therefore identical with the extinction coefficient per mole of retinene (40,600 cm.2 per mole) and the E(1 per cent, 1 cm., 500 mµ) has a value of about 10. Rhodopsin constitutes about 14 per cent of the dry weight, and 3.7 per cent of the wet weight of cattle outer limbs. This corresponds to about 4.2 x 106 molecules of rhodopsin per outer limb. The rhodopsin content of frog outer limbs is considerably higher: about 35 per cent of the dry weight, and 10 per cent of the wet weight, corresponding to about 2.1 x 109 molecules per outer limb. Thus the frog outer limb contains about five hundred times as much rhodopsin as the cattle outer limb. But the relative volumes of these structures are such that the ratio of concentrations is only about 2.5 to 1 on a weight basis. Rhodopsin accounts for at least one-fifth of the total protein of the cattle outer limb; for the frog, this value must be higher. The extinction (K500) along its axis is about 0.037 cm.2 for the cattle outer limb, and about 0.50 cm.2 for the frog outer limb.

Biogenic synthesis of Au and Ag nanoparticles using aqueous solutions of Black Tea leaf extracts

2009 ◽  
Vol 71 (1) ◽  
pp. 113-118 ◽  
Author(s):  
Naznin Ara Begum ◽  
Samiran Mondal ◽  
Saswati Basu ◽  
Rajibul A. Laskar ◽  
Debabrata Mandal
Keyword(s):  
Aqueous Solutions ◽  
Ag Nanoparticles ◽  
Black Tea ◽  
Leaf Extracts ◽  
Biogenic Synthesis ◽  
Tea Leaf

Influence of Temperature and Water Activity on Aflatoxin Production by Aspergillus flavus in Cowpea (Vigna unguiculata) Seeds and Meal

1985 ◽  
Vol 48 (12) ◽  
pp. 1040-1043 ◽  
Author(s):  
P. E. KOEHLER ◽  
L. R. BEUCHAT ◽  
M. S. CHHINNAN
Keyword(s):  
Heat Treatment ◽  
Water Activity ◽  
Aspergillus Flavus ◽  
Vigna Unguiculata ◽  
Dry Weight ◽  
Aflatoxin Production ◽  
Weight Basis ◽  
Influence Of Temperature

Experiments were done to determine the influence of temperature (21, 30 and 37°C) and aw (0.76 to 0.98) on aflatoxin production by Aspergillus flavus on cowpea (Vigna unguiculata) seeds, meal and meal supplemented with onion. Larger quantities of aflatoxin were produced at 21 and 30°C than at 37°C. The highest amount of aflatoxin (2777 μg/20 g, dry weight basis) was observed in meal containing onion at aw 0.98 after 20 d of incubation at 21°C. A level of 870 |μg/20 g was detected in seeds at aw 0.95 after 14 d of incubation at 30°C. Meal at aw 0.96 supported production of 551 μg of aflatoxin per 20 g after 20 d at 30° C. Temperature had little influence on the optimal aw for aflatoxin production in cowpea meal. However, an increase in temperature resulted in a decreased optimal aw for aflatoxin production on whole cowpeas. When known quantities of aflatoxin were added to cowpea meal which was subsequently steamed for 5 min, only 29% was extractable using a variety of procedures, indicating that the toxin may be bound in some manner to cowpea constituents as a result of heat treatment.

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