Sampling Tube Articles

  • Joint estimation of hydraulic conductivities of two sand samples in a W-tube system with a bi-exponential response

    The motivation for this paper is the practical problem of interpreting bi-exponential rate-of-rise curves that are observed during many field piezometric tests. In the authors' previous study, a laboratory W-tube system of water flow through two samples of sand was introduced with an adequate mathematical model. The desired bi-exponential character of water flow was obtained by placing two ...


    By IWA Publishing

  • How can I keep my samples secure and tamper proof?

    The first stage of any test is to collect a sample. Whether it’s water, biological tissues, or a sample from a production line, it must be representative of the bulk and not be altered in order to give accurate results. Most samples will have to be transported after they are collected – this might be just a few meters from a production line to the test room, or could be ...


    By Camlab Limited

  • Sampling of Carbonyls Using a Dual-Layer LpDNPH Glass Sampling Tube and HPLC Analysis

    The dual-layer LpDNPH sorbent tube is an air sampling device designed for sampling carbonyls (e.g. formaldehyde) in ambient, indoor, and industrial atmospheres. Carbonyls are trapped on our high-purity silica gel adsorbent coated with 2,4-dinitrophenylhydrazine (2,4-DNPH) where they are converted to stable hydrazone derivatives. The derivatives are eluted from the tube in acetonitrile and ...


    By Sigma-Aldrich Co., LLC

  • Evaluation of the test of significant toxicity for determining the toxicity of effluents and ambient water samples

    The test of significant toxicity (TST) is a hypothesis‐testing approach based on bioequivalence developed by the U.S. Environmental Protection Agency (U.S. EPA) for analyzing whole‐effluent toxicity (WET) and ambient toxicity data. The present study compares results of acute and chronic toxicity tests of effluent, storm‐water, and ambient (i.e., receiving‐water) samples using both the TST and ...


    By John Wiley & Sons, Ltd.

  • Carbonyl Sampling and Analysis by HPLC

    Sampling of Carbonyls Using a Dual-Layer LpDNPH Glass Sampling Tube and HPLC Analysis with an Ascentis Express C18 Column The dual-layer LpDNPH ORBO-555 tube is an effective sampler for measuring airborne carbonyl concentration. The low background levels in the sampler allow for accurate measurements of low concentration samples or samples collected in ...


    By Sigma-Aldrich Co., LLC

  • Dialysis with a semipermeable membrane – a new sample-preparation technique for determination of Polybrominated Diphenyl ethers in fatty matrices

    Summary Dialysis with a low-density polyethylene semipermeable membrane (SPM) is an efficient means of removal of lipids in the determination of bioaccumulative, persistent, halogenated organic compounds. In this study an SPM was used for preconcentration of polybrominated diphenyl ethers (PBDE) from food samples. The method is useful for determination of PBDE and other halogenated ...


    By Exposmeter AB

  • Fermentation tube test statistics for direct water sampling and comments on the Thomas formula

    This article describes a new interpretation of the Fermentation Tube Test (FTT) performed on water samples drawn from natural waters polluted by faecal bacteria. A novel general procedure to calculate the Most Probable Number of bacteria (MPN) in natural waters has been derived for the FTT for both direct and independent repetitive multiple water sampling. The generalization based on solving the ...


    By IWA Publishing

  • Detection of chlorpyrifos in air using low volume polyurethane foam (PUF) sampling with immunoassay

    MATRIX: Air samples ANALYTE: Chlorpyrifos RANGE OF DETECTION: 0.088 to 1.200 mg/m3 MATERIALS: Chlorpyrifos RaPID AssayÒ Kit and Sample Diluent. Reagents: methanol (pesticide grade). Equipment: 40 mL glass vials with Teflon lined caps, 13 x 100 mm glass test tubes, 5 mL and 20 mL serological pipets, micropipet ...


  • Atrazine accuracy confirmation using EPA certified reference standard

    ANALYTE: Atrazine RANGE OF EVALUATION: 0.5 to 4.0 ppb MATERIALS: Atrazine RaPID Assay Kit and Sample Diluent (cat. no. A00051) Reagents: U.S. EPA Reference Standard for atrazine with certified concentration of 1000 μg/mL, in methanol ( NSI Environmental Solutions, Research Triangle Park, NC). Equipment: precision micropipets: 100 ...


  • 2,4-D accuracy confirmation using EPA certified reference standard

    ANALYTE: 2,4-D RANGE OF EVALUATION: to 40 ppb MATERIALS: 2,4-D RaPID Assay Kit and Sample Diluent (cat. no. A00079) Reagents: U.S. EPA Reference Standard for 2,4-D with certified concentration of 5000 μg/mL, in acetonitrile (N SI Environmental Solutions, Research Triangle Park,N C). Equipment: 100 μL ...


  • Liquid application

    The CLD 88 enables to detect down to pMol level (nitrite / nitrate levels in drinking water).The new sample tube we are using (type 1), is optimized for this application. The internal flow restriction ismade from stainless steel and it can be cleaned in an ultrasonic cleaner. The sample flow of 110 ml/minminimizes the effect of the helium bubbles in the liquid sampler, which results in very low ...


    By ECO PHYSICS INC.

  • Installing Continuous Multi-Chamber Tubing Using Sonic Drilling

    As a geologist, core is the first thing that comes to mind when talking about sonic drilling— continuous, near complete core recovery through almost any lithology. Sand to silt transitions can be logged on a centimeter scale if desired. Geologic contacts can be mapped with accuracy of less than one foot. In an environmental ground water assessment, it seems an awful shame to collect (and pay for) ...


    By Solinst Canada Ltd.

  • Sampling trace-level organic solutes with polymeric tubing. Part 2. Dynamic studies

    Parker and Ranney present the results of laboratory tests focused on investigation the potential positive or negative biases associated with using polymetric tubing to collect groundwater samples. This paper, the second in a series, focuses on the effects under dynamic (i.e., pumping) conditions. They show that negative biases are a function of the plymer material, the hydrophobicity of the ...


    By Solinst Canada Ltd.

  • Analysis of Stack Emissions Using VOST Air Sampling Tubes and Capillary GC

    United States EPA SW-846, Method 0030, Volatile Organic Sampling Train (VOST), describes the sampling of emissions for volatile compounds from hazardous waste incinerator stacks. Supelco's VOST air sampling tubes are designed to fulfill the method requirements and provide low background levels.               ...


    By Sigma-Aldrich Co., LLC

  • A Simulation of Tube Sampling Effects on the Stiffness of Clays

    The effect of tube sampling disturbance on the prefailure behavior of reconstituted kaolin was investigated in the triaxial cell. Previously published forms of stress paths followed by normally consolidated and overconsolidated clays during simulated sampling have been substantiated. After the initial stresses were restored, the behavior of the undisturbed clay at small strains (up to 0.1%) was ...


    By ASTM International

  • Monitor Organophosphorus Pesticides in Air, Using ORBO-49P Tubes and Capillary GC

    A sampling tube containing Supelpak-20 resin and a glass fiber filter effectively adsorbs and releases five organophosphorous pesticides (chlorpyrifos, diazinon, dichlorvos, malathion, parathion) in vapor or aerosol form in air.  At a sampling rate of 1L/min, 8 hour samples can be taken for all of these pesticides except malathion.  Short term (15 min) samples can be taken at the same ...


    By Sigma-Aldrich Co., LLC

  • The Preparation of Hollow Cylinder Specimens from Undisturbed Tube Samples of Soft Clay

    The use of torsional-hollow cylinder testing apparatus for research into soil stress-strain behavior has grown over the past decade. Most studies have focused on sands or on cohesive materials reconstituted in the laboratory. Studies involving undisturbed soft clay have been neglected, in part due to the difficulties involved in specimen preparation.The present paper describes a procedure for the ...


    By ASTM International

Need help finding the right suppliers? Try XPRT Sourcing. Let the XPRTs do the work for you