Tuesday 29 June 2010

AOAC Official Method 2000.04 Iodine-131 in Milk Radiochemical Separation Method First Action 2000

(Applicable to determination of iodine-131 in milk at 0.1-0.3 Bq/L.)
Caution:    This method requires the use of a chlorinated solvent, C(b), a suspected and possible human carcinogen.
See Table 2000.04 for the results of the interlaboratory study supporting acceptance of the method.

A. Principle

The test portion is treated with NaHSO3 to convert all the iodine to a common (I-) oxidation state. Iodide is isolated and concentrated on an ion-exchange column. The iodide is oxidized on-column to iodate by NaOCl solution and eluted by this solution. The NaOCl is decomposed and the iodate is reduced by hydroxylamine hydrochloride solution to elemental iodine which is extracted by CC14. The iodine is again reduced to iodide and re-extracted into aqueous solution by NaHSO3 solution. The iodide is coprecipitated with palladium iodide (PdI2) and the recovery of the carrier is determined gravimetrically. The iodine-131 in the carrier is counted by a beta-gamma coincidence or by a low-background beta counter.

AOAC Official Method 2000.03 Ochratoxin A in Barley Immunoaffinity by Column HPLC First Action 2000

(Applicable to the determination of ochratoxin A in barley at >1 ng/g)
See Table 2000.03A for results of the interlaboratory study supporting the acceptance of the method.

A. Principle

Test portion is extracted by blending with acetonitrile-water. The extract is cleaned up by passing through an immunoaffinity column. Ochratoxin A (OTA) is eluted with methanol, further purifed and identified by LC, and quantified by fluorescence.

AOAC Official Method 2000.02 Patulin in Clear and Cloudy Apple Juices and Apple Puree Liquid Chromatographic Method First Action 2000

(Applicable to determination of patulin at >25 ng/g in clear apple juice, cloudy apple juice, and apple puree.)
See Table 2000.02 for results of the interlaboratory study supporting the acceptance of the method.

A. Principle

Apple juice or puree is extracted with ethyl acetate and then cleaned up by extraction with sodium carbonate solution. (Cloudy apple juice and apple purees are pretreated with pectinase enzyme.) The ethyl acetate extract is dried with anhydrous sodium sulfate. After evaporation of the solvent, patulin is quantitatively determined by LC with UV detection.

AOAC Official Method 2000.01 Determination of 3-Chloro-1,2-Propanediol in Foods and Food Ingredients Gas Chromatography/Mass Spectrometric Detection First Action 2000

[The method is applicable to the determination of 3-chloro-1,2-propanediol (3-monochloropropane-1,2-diol; 3-MCPD) in hydrolyzed vegetable protein (HVP), soups and stocks, stock cubes, soy sauce, malt extract, salami, fish, cheese, flour, starch, cereals, and bread.]
Caution:    This work should be performed under a fume hood. Wear laboratory coat, gloves, and eye/face protection. Use double-containment systems for handling concentrated solutions of 3-MCPD-d5. Take care to avoid ignition of flammable reagents by sparks or static discharge.
See Table 2000.01 for the results of the interlaboratory study supporting acceptance of the method.

A. Principle

Internal standard 3-chloro-1,2-propanediol-d5 (3-MCPD-d5) is added to the test portion, followed by salt solution, and the mixture is blended to a homogeneous consistency. After sonication, the contents of an ExtrelutTM refill pack are added and mixed thoroughly. The mixture is transferred to a glass chromatographic tube, and the nonpolar components are eluted with a mixture of hexane and diethyl ether. The 3-MCPD is eluted with diethyl ether, and the extract is concentrated to a small volume. A portion of the concentrated extract is derivatized and analyzed by gas chromatography with mass spectrometric detection (GC/MS). The concentration of 3-MCPD is expressed in mg/kg.

AOAC Official Method 2002.05 Determination of Cholecalciferol (Vitamin D3) in Selected Foods Liquid Chromatography First Action 2002

A. Principle

After the addition of an internal standard (vitamin D2) and basic hydrolysis, vitamin D3 is extracted with n-heptane. The fraction that contains vitamin D2/D3 is separated by preparative normal-phase liquid chromatography (LC). After evaporation and dilution in acetonitrile–methanol, vitamin D3 is determined by reversed-phase LC with UV detection at 265 nm. A separate test portion is analyzed in parallel to confirm the absence of endogenous vitamin D2.

AOAC Official Method 2002.04 Amylase-Treated Neutral Detergent Fiber in Feeds Using Refluxing in Beakers or Crucibles First Action 2002

A. Principle

Fiber in feeds is a nutritionally defined entity that represents the indigestible and slowly digesting fraction of feeds. Neutral detergent (ND) solution and heat-stable alpha.gif (53 bytes)-amylase are used to dissolve easily digested proteins, lipids, sugars, starches, and pectins in feeds, leaving a fibrous residue that is primarily cell wall components in plant materials (cellulose, hemicellulose, and lignin) and indigestible nitrogenous matter in animal products. aNDF is a gravimetric method that best estimates the total insoluble fiber, and is inversely related to digestibility and intake potential of a feed. ND soluble matter is almost completely digested by most animals; however, the digestibility of aNDF is variable among feeds and is related to lignin and other constituents in fiber.
Sodium lauryl sulfate, an anionic detergent, and sodium sulfite are used to solubilize nitrogenous matter; EDTA is used to chelate calcium and enhance removal of pectins at boiling temperatures; triethylene glycol helps remove some nonfibrous matter from concentrated feeds; disodium phosphate and sodium borate are used as buffers to maintain a neutral pH.
Hot ND solution has limited ability to solubilize starch; therefore, a heat-stable amylase is used to hydrolyze starch to saccharides that can be easily removed from fiber by filtration. Heat-stable amylases are used in hot solutions to inactivate potential contaminating enzymes in crude amylase extracts that might degrade fibrous constituents. To ensure that the amylase activity is sufficient to remove most starch and to reduce filtering difficulties, the amount of any specific amylase source needed to measure aNDF is determined under the conditions of the aNDF method.
Although boiling ND solution dissolves most proteins, lipids, and nonfibrous carbohydrates, these constituents are nonviscous only in water that is near boiling temperature. Therefore, boiling water is needed for washing fibrous residues and removing nonfibrous matter. Because fiber is particulate matter, mass-action equilibration during soaking is needed to migrate ND and contaminating soluble matter from the interior of fiber particles. Fibrous residues must be soaked, instead of being simply rinsed, in near boiling water to remove nonfibrous matter.
Boiling ND solution solubilizes lipids, and acetone soaking of the residue completes the extraction of lipids and pigments in most materials. However, excessive amounts of lipids in materials can complex with the detergent and reduce extraction efficiency. Because extraction of lipids by ND and acetone may be incomplete when feeds contain >10% lipid, these materials are pre-extracted to ensure complete removal of lipid contamination from fiber. Pre-extract materials with 5–10% lipid to minimize filtration difficulties and avoid variable aNDF results.

AOAC Official Method 2002.03 Pesticide Residues in Nonfatty Foods Supercritical Fluid Extraction and Gas Chromatography/Mass Spectrometry First Action 2002

A. Principle

A chopped frozen fruit or vegetable test portion is mixed with a drying agent, and the pesticide residue is extracted by using supercritical CO2, collected on a solid-phase sorbent or in a liquid trap, and determined by GC/MS.

AOAC Official Method 2002.02 Resistant Starch in Starch and Plant Materials Enzymatic Digestion First Action 2002

A. Principle

Nonresistant starch is solubilized and hydrolyzed to glucose by the combined action of pancreatic alpha.gif (53 bytes)-amylase and amyloglucosidase (AMG) for 16 h at 37°C. The reaction is terminated by addition of ethanol or industrial methylated spirits (IMS) and RS is recovered as a pellet by centrifugation. RS in the pellet is dissolved in 2M KOH by vigorously stirring in an ice–water bath. This solution is neutralized with acetate buffer and the starch is quantitatively hydrolyzed to glucose with AMG. Glucose is measured with glucose oxidase–peroxidase reagent (GOPOD), which is a measure of RS content. Nonresistant starch (solubilized starch) is determined by pooling the original supernatant and the washings and measuring the glucose content with GOPOD.

AOAC Official Method 2002.01 Measurement of alpha.gif (53 bytes)-Amylase Activity in White Wheat Flour, Milled Malt, and Microbial Enzyme Preparations Ceralpha Assay First Action 2002

A. Principle

Test portions are extracted with salt solution or buffer at room temperature or 40°C. Extracts are clarified by centrifugation or filtration and diluted. Aliquots of diluted extract are incubated with the substrate mixture under defined conditions of pH, temperature, and time. The substrate is nonreducing end-blocked p-nitrophenyl maltoheptaoside (BPNPG7) in the presence of excess quantities of thermostable alpha.gif (53 bytes)-glucosidase. The blocking group in BPNPG7 prevents hydrolysis of this substrate by exo-acting enzymes such as amyloglucosidase, alpha.gif (53 bytes)-glucosidase, or beta.gif (844 bytes)-amylase. When the substrate is cleaved by endo-acting alpha.gif (53 bytes)-amylase, the nitrophenyl oligosaccharide is immediately and completely hydrolyzed to p-nitrophenol and free glucose. The reaction is terminated, and the phenolate color developed by the addition of an alkaline solution is measured at 400 nm. Results are expressed in Ceralpha units; 1 unit is defined as the amount of enzyme required to release (in the presence of excess alpha.gif (53 bytes)-glucosidase) 1 µmol p-nitrophenol per minute at 40°C

44.1.12 - Sugars and Sugar Products / Sugars and Syrups

AOAC Official Method 896.02
Sucrose in Sugars and Syrups

Double Dilution Method
First Action 1896
Final Action 1970


Reference:
Analyst 21, 182(1896).

33.2.21 - Dairy Products / Milk

AOAC Official Method 896.01
Lactose in Milk

Polarimetric Method
First Action 1896
Final Action


References:
Analyst 21, 182(1896).
JAOAC 25, 603(1942); 27, 232(1944).
CAS-63-42-3 (lactose)

41.1.53 - Oils and Fats

AOAC Official Method 893.01
Oil (Sesame) in Oils and Fats

Modified Villavecchia Test
First Action 1893
Final Action


References:
J. Soc. Chem. Ind. 12, 67(1893); 13, 69(1894). JAOAC 6, 441(1923).
CAS-8008-74-0 (sesame oil)

Food Additives: Direct / Chemical Preservatives

AOAC Official Method 892.02
Sulfurous Acid (Free) in Meats

Titrimetric Method
First Action 1892
Final Action

References:
J. Prakt. Chem. 46, 428(1892).
Repts. on Public Health and Med. Subject No. 43 (London, Ministry of Health, p. 12).
CAS-7446-09-5 (sulfur dioxide)
CAS-7782-99-2 (sulfurous acid

AOAC Official Method 892.01 Nitrogen (Ammoniacal and Nitrate) in Fertilizers Devarda Method First Action 1892 Final Action

AOAC Official Method 892.01
Nitrogen (Ammoniacal and Nitrate)
in Fertilizers

Devarda Method
First Action 1892
Final Action

AOAC Official Method 871.01 Oil (Peanut) in Oils and Fats Modified Renard Test First Action 1871 Final Action

AOAC Official Method 871.01
Oil (Peanut) in Oils and Fats

Modified Renard Test
First Action 1871
Final Action

Monday 28 June 2010

Assessment of heavy metal contamination in soils at Jajmau (Kanpur) and Unnaoindustrial areas of the Ganga Plain, Uttar Pradesh, India

Environmental geochemical studies were carried out in and around Jajmau (Kanpur) and Unnao industrial areas (80◦15 –80◦34 E longitude and 26◦24 –26◦35 Nlatitude), of Uttar Pradesh to find out the extent of chemical pollution in soil due to industrial waste. Jajmau and Unnao are prominent centers for leather processing clusters of tannery industries (about 450) along the banks of river Ganga, besides other industries. Geologically the study area is beset with alluvium of Quaternary age consisting of older alluvium of middle to upper Pleistocene and newer alluvium of Holocene. The climate of the study area is semi-arid type. Fifty-three soil samples were collected from Jajmau and Unnao industrial areas from top 15cm layer of the soil and were analyzed for heavy metals by using Philips MagiX PRO-PW 2440 X-ray fluorescence spectrometer. The data reveals that the soil in the area is significantly contaminated with heavy metals such as chromium varies from 161.8 to 6227.8 mg/kg (average of 2652.3 mg/kg), Ba varies from 44.1 to 780.9 mg/kg (average of 295.7 mg/kg), Cu varies from 1.7 to 126.1 mg/kg (average of 42.9 mg/kg), Pb varies from 10.1 to 67.8 mg/kg (average of 38.3 mg/kg), Sr varies from 46.6 to 150.6 mg/kg (average of 105.3 mg/kg), V varies from 1.3 to 208.6 mg/kg (average of 54.4 mg/kg) and Zn varies from 43.5 to 687.6 mg/kg (average of 159.9 mg/kg). Soil contamination was assessed on the basis of geoaccumulation index, enrichment factor (EF), contamination factor and degree of contamination. Indiscriminate dumping of hazardous waste in the study area could be the main cause of the soil contamination, spreading by rainwater and wind. Distribution and correlation of heavy metals in soil along with possible remedial measures are discussed.

Assessment of Water Quality Status for the Selangor River in Malaysia

 

Abstract Water quality degradation in the Selangor River will still be present in the years to come since pollutant loads from poultry farms, municipal wastewaters, and industrial wastewaters are not envisaged to be handled effectively. This will be facing the problems of water quality status to use for multiple purposes and to provide its aquatic environment continuously. The water quality evaluation system is used to assess the water quality condition in the river. This system distinguishes two categories of water condition i.e., the water quality index and water quality aptitude. The assessment of water quality for the Selangor River from nine stations along the main stream, which concludes that water has been highly polluted (index 5) immediately downstream of station 02 Selangor River before confluence with Kubu River due to high concentration of microorganisms and immediately downstream of station 06 Selangor River before confluence with Batang Kali River due to high concentrations of microorganisms and suspended particles, was verified. Mineral micropollutants were found to gradually pollute the stream water, ranging from the unpolluted water (index 1) in the upstream to the bad quality (index 4) in the downstream area.

Animal feeding stuffs Determination of OC-pesticides and PCB's by GC/ECD BS EN 15742:2009

This European Standard specifies a gas chromatographic method with electron capture detection (ECD) for the determination of organochlorine pesticides (OC’s) and polychlorinated biphenyls (PCBs) in animal feeding stuffs. The method is applicable to animal feeding stuffs with a water content up to about 20 wt% and oil/fatty samples containing residues of one or more of the following OC’s, PCBs, toxaphene and some of their isomers and degradation products:
 Aldrin;
 Dieldrin;
 Chlorocamphene (Toxaphene);
 Chlordane (= sum of Chlordane isomers and Oxychlordane);
 DDT (= sum of isomers op'-DDT, pp'-DDT, pp'-TDE (pp'-DDD), and pp'-DDE);
 Endosulfan (sum of α-/β-isomers and Endosulfan-sulphate);
 Endrin;
 Heptachlor (= sum of Heptachlor and β-Heptachlorepoxide);
 Hexachlorobenzene (HCB);
 Hexachlorocyclohexane isomers α-HCH (α-BHC), β-HCH (β-BHC), γ-HCH (γ-BHC or lindane);
 PCB 28, 52, 101, 138, 153 and 180 (“Indicator PCBs”) and PCB 198, 209.
The limit of quantification for the mentioned organochlorine pesticides and PCBs is 5 ng/g in general. However, 10 ng/g applies for Heptachlor, Aldrin, Endrin, Dieldrin, and Endosulfan (α-, β- and sulphate). Individual laboratories are responsible to ensure that the equipment they used will achieve these limits of
quantifications

Sunday 27 June 2010

Dichromate Reflux A Proposed Method for Chemical Oxygen Demand Chloride Correction in Highly Saline Wastes

Any method that attempts to determine chemical oxygen demand (COD) by strong wet oxidative means in saline wastes encounters the problem of chloride interference. Chloride oxidation can be avoided by using mild oxidizing conditions but only at the expense of inefficient oxidation of organic matter. The standard procedure ( I ) for the determination of COD by the dichromate reflux method utilizes acid concentrations and heating times which will oxidize roughly 85-95’70 of the organic matter present but will also oxidize essentially 100% of the chloride ion (2). In the standard procedure, interference by chloride ion, at moderate concentrations, is largely prevented through the addition of mercuric sulfate to form unionized mercuric chloride (3). The complexing method, as currently practiced, using a weight ratio of HgS04:Cl equal to 1O:l will yield reproducible results at chloride concentrations up to 5,000 mg/l. Problems due to chloride interference arise in wastes of low to moderate COD with chloride concentrations approaching that of sea water.

Water quality Detection and enumeration of Escherichia coli and coliform bacteria EN ISO 9308−1:2000 BS EN ISO 9308-1:2000

The presence and extent of faecal pollution is an important factor in assessing the quality of a body of water and the risk to human health from infection. Examination of water samples for the presence of Escherichia coli, which normally inhabits the bowel of man and other warm-blooded animals, provides an indication of such pollution. Examination for coliform bacteria can be more difficult to interpret because some coliform bacteria live in soil and surface fresh water, and are not always intestinal. Therefore, the presence of coliform bacteria, although not a proof of faecal contamination, may indicate failure in treatment or distribution. The identification of the strains isolated can sometimes provide an indication of their origin.

Methods of test for Soils for civil engineering purposes BS 1377-3:1990

This Part of BS 1377 has been prepared under the direction of the Road Engineering Standards Policy Committee. It is a revision of clause 3 of BS 1377:1975 which is superseded by amendment. BS 1377 was first published in 1948 and first appeared in metric form in 1975. BS 1377:1975 which has now been withdrawn is replaced by the following Parts of BS 1377:1990:
— Part 1: General requirements and sample preparation;
— Part 2: Classification tests;
— Part 3: Chemical and electro-chemical tests;
— Part 4: Compaction-related tests;
— Part 5: Compressibility, permeability and durability tests;
— Part 6: Consolidation and permeability tests in hydraulic cells and with pore pressure measurement;
— Part 7: Shear strength tests (total stress);
— Part 8: Shear strength tests (effective stress);
— Part 9: In-situ tests.
Reference should be made to Part 1 for further information about each of the Parts. In this Part of BS 1377 the test methods described in the 1975 edition have been retained with some modification, and the following methods of test have been introduced:
a) determination of loss on ignition;
b) determination of carbonate content;
c) determination of chloride content;
d) determination of total dissolved solids content;
e) determination of electrical resistivity;
f) determination of the redox potential;

Part 1: Guidance on the design of sampling programmes and sampling techniques EN ISO 5667-1:2006

This part of ISO 5667 sets out the general principles for, and provides guidance on, the design of sampling programmes and sampling techniques for all aspects of sampling of water (including waste waters, sludges, effluents and bottom deposits). It does not include detailed instructions for specific sampling situations, which are covered in the various other parts of ISO 5667. Also, it does not include microbiological sampling, which is covered in ISO 19458 [23].

Thursday 24 June 2010

Section 2.7 Determination of ammonium: distillation and titration method

Scope
This International Standard specifies a distillation and titration method for the determination of ammonium in raw, potable and waste water.An ammonium nitrogen content of up to 10 mg in the test portion may be determined. Using a 10 ml test portion, this corresponds to a sample concentration of up to A’N P = 1 000 mg/l.

Water quality Part 2: Physical, chemical and biochemical methods BS 6068-2.34:1988

The chemical oxygen demand, COD, of water as determined by this dichromate method can be considered as an approximate measure of the theoretical oxygen demand, i.e. the amount of oxygen consumed in total chemical oxidation of the organic constituents to inorganic end products (see also clause 9). The degree to which the test results approach the theoretical value depends primarily on how complete the oxidation is. A great number of organic compounds are oxidized to an extent of between 90 % and 100 %, and for waters where these compounds predominate, such as municipal effluents, the COD value is a realistic measure of the theoretical oxygen demand. For other waters which contain large quantities of certain substances that are difficult to oxidize under the conditions of the test (see clause 9), the COD value is a poor measure of the theoretical oxygen demand. This may be the case for some industrial effluents. The significance of a COD value thus depends on the composition of the water studied. This should be borne in mind when judging results obtained by the method described in this Section of BS 6068.

Tumor Self-Seeding by Circulating Cancer Cells


Summary

Cancer cells that leave the primary tumor can seed metastases in distant organs, and it is thought that this is a unidirectional process. Here we show that circulating tumor cells (CTCs) can also colonize their tumors of origin, in a process that we call “tumor self-seeding.” Self-seeding of breast cancer, colon cancer, and melanoma tumors in mice is preferentially mediated by aggressive CTCs, including those with bone, lung, or brain-metastatic tropism. We find that the tumor-derived cytokines IL-6 and IL-8 act as CTC attractants whereas MMP1/collagenase-1 and the actin cytoskeleton component fascin-1 are mediators of CTC infiltration into mammary tumors. We show that self-seeding can accelerate tumor growth, angiogenesis, and stromal recruitment through seed-derived factors including the chemokine CXCL1. Tumor self-seeding could explain the relationships between anaplasia, tumor size, vascularity and prognosis, and local recurrence seeded by disseminated cells following ostensibly complete tumor excision.

Oil spill identification Waterborne petroleum and petroleum products PD CEN/TR 15522-1:2006

Where an oil pollution incident has occurred, samples should be collected from both the spill and, wherever possible, the potential source of the pollutant, e.g. ship, shore tank, pipeline or road vehicle, in order to assist in the identification or confirmation of the source of the spill. The aim of this document is to give guidance on the best current practice for taking such samples. This document does not contain details relating to all types of spill situation, but should only be regarded as general guidelines. However, by following these guidelines it should be possible to collect and provide legally valid samples that can be used in the process of identifying or confirming the source of the spill. The issues addressed only cover the mechanics of sample collection. The command and control that may be put in place during incident response, the authorities who may request sample collection and the individuals who have the authority to collect samples, will vary from country to country and as a consequence these issues are not addressed

The Environmental Impact of Shrimp Aquaculture and the Coastal Pollution in Mexico

The moderated, but continual development of the shrimp aquaculture in Mexico, in conjunction with municipal and agriculture effluents, in the last decade has created the first symptoms of negative environmental impacts, due mainly to the discharge of nutrients and organic matter into adjacent coastal waters. Similarly, the increasing impairment of coastal water quality resulting from the discharge of domestic, agricultural and industrial wastes into coastal waters has affected the aquaculture profitability in certain areas. The cumulative impact of the main anthropogenic sources of nutrients in the Mexican coastal states was estimated in 190 088 ton N yr-1 and 51 831 ton P yr -1. The input from shrimp aquaculture is only 1.5% and 0.9% of the main sources of nitrogen and phosphorus. This last input, though small, is related to local and adverse effects on coastal ecosystems. The introduction of management measures to mitigate the adverse environmental impacts of shrimp aquaculture development has now become necessary and urgent

Wednesday 23 June 2010

X-FEM analyses of a thin-walled composite shell structure with a delamination

The extended finite element method is applied to stress analyses of composite laminates modeled by shell elements. In the proposed method, a thin-walled structure containing an interface is modeled by shell elements, and the nodes on the interface are enriched in order to model the delamination. The X-FEM code for thin-walled structures based on the proposed method is developed and is applied to buckling analyses of Carbon Fiber-Reinforced Plastic laminate with delaminations. The proposed X-FEM for shell elements was shown to provide appropriate results, which agree well with those obtained by the X-FEM for solid elements and conventional FEM analyses.

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