Analytical reagent grade chemicals

Materials. Aldicarb standards were obtained from the United States Environmental Protection Agency (USEPA), Quality Assurance Section and from Union Carbide Corporation. Crystalline samples of carbofuran and 3-hydroxycarbofuran were supplied by the Agricultural Chemical Group of FMC Corporation. Reference standards of methomyl (99% pure) and oxamyl (99% pure) were obtained from USEPA. HPLC grade methanol was purchased from Burdick and Jackson, Inc. Methylene chloride used for bulk extractions of the carbamate pesticides in solution was recovered, distilled and reused. Analytical reagent grade chemicals and solvents were used in all experiments. Doubly distilled deionized water was used for solution rate studies. Deionized distilled water (DDW) was used for dilutions in reactive ion exchange experim ts., , ... 

Commercially available aqueous standard stock solutions or solutions prepared from analytical reagent grade chemicals may be used. Dilute these to give calibration standards approximately in the range given in Section IV.A.l. 

Only established analytical reagent grade chemicals should be employed for the preparation of standards and reagent solutions and the treatment of samples. 

Solutions were made using analytical reagent grade chemicals in Hillipore "Super-Q water. Artificial seawater was prepared as previously described (2). 

Reagents. Unless otherwise indicated, materials were obtained from commercial suppliers and used without further purification. Analytical reagent grade chemicals were used along with deionized water to prepare solutions. Europium (III) oxide, styrene, vinyl benzoate, AIBN, mediyl phosphonic acid and pinacolylmethyl phosphonate were obtained from Aldrich (Aldrich, Milwaukee, WI S3233). Neat analytical standards of the pesticides and insecticides were obtained from Radian (Radian International, Austin, TX 78720). Parathion, methyl-parathion, tfaionazin, and dibutyl chlorendate were obtained as neat standards from Supelco (Supelco Chromatography Products, Bellefonte, PA 16823). 

The analytical reagent grade chemical may contain a trace of copper and should be redistilled from all-glass equipment before use. Store the purified solvent in a dark glass bottle. 

Reagent-Grade Chemicals. Potassium dichromate is an important analytical standard, and other chromium chemicals, in reagent grades, find considerable laboratory use (90,91). This use, though small, is most important in wet analyses. 

Xylene (analytical reagent grade) from Mallinckrodt Chemical Works was distilled from sodium before use. 

Chemical Reagents. Wherever chemical reagents are specified in the following tests, analytical reagent grade shall be used... 

Analytical reagent-grade sodium azide purchased from Alfa Division, Ventron Corporation, or J. T. Baker Chemical Company was used as supplied. 

Pyridylcarbinol, 4-acetylpyridine, 3-pyridine-carboxaldehyde and 4-aminomethylpyridine were obtained from Aldrich Chemical Company (Milwaukee, Wisconsin) and were purified by distillation at reduced pressure. 4-Benzoylpyridine was recrystallized from ethanol. 4-Aminopyridine (G. Frederick Smith Chemical Company), isonicotinic acid (Aldrich) and isonicotinamide (Aldrich) were used as received. Triply distilled water was used. All other reagents were analytical reagent grade. 

All other chemicals were analytical reagent grade. All solvents were redistilled in glass. 

The submitters used anhydrous, sublimed aluminum chloride obtained from E. Merck AG, Darmstadt, Germany. The checkers used analytical reagent grade material obtained from Mallinckrodt Chemical Works. 

Unless otherwise stated all chemicals should be of Analytical Reagent grade or equivalent. 

Chloroform, ethyl acetate, methanol and alkaloids were of analytical reagent grade, diethylamine was chemically pure. All reagents were used without further purification. Solutions of the alkaloids were made at concentrations of 1 mg/ml by dissolving in methanol. 20 10 cm, precoated silicagel 60 F-254 TLC plates (Merck) were used. The plates were presaturated in a temperature and humidity controlled tank for 60 minutes. With disposable micropipettes a 2 pi sample was spotted 1 cm from the lower edge of the plate. The spots were detected with the help of an UV lamp at 254 nm. 

Laboratory personnel commonly give one of three common responses to someone who points out the traceability requirements of ISO/fEC 17025 Its ok we have our balances calibrated every year, and when it is further pointed out that calibration extends to the chemical aspects of the measurement, I am sure it is ok to use this analytical-reagent-grade material to make a calibration solution, or we make measurements in such complex matrices, a suitable CRM just does not exist. The first comment stems from the rather physical or engineering flavor of the section in ISO/IEC 17025 (section 5.6) (ISO/IEC 2005), although traceability of calibration materials is mentioned. 

Mallinckrodt analytical reagent grade ether, dried over sodium, was used. The methyl borate was the commercial product of American Potash and Chemical Corporation containing 99% ester as received. The phenylmagnesium bromide was purchased as a 3.0M solution in ether from Arapahoe Special Products, Inc., Boulder, Colorado. 

Copper(I) chloride, S.L.R. grade, was used as supplied by Fisons Scientific Apparatus Ltd. Best results are obtained with fresh samples of copper(l) chloride which usually contains 2 copper(II) chloride. Further purification4 did not improve the yield of BTMSBD. The checkers used Mallinckrodt Chemical Company, Analytical Reagent Grade copper(I) chloride, without further purification. 

All chemicals used are of analytical-reagent grade, and water is obtained from a Millipore Milli-Q purification system. 

The calf thymus dsDNA and ssDNA (as lyophilized powder) were obtained from Sigma-Aldrich Company (Germany). dsDNA/ssDNA stock solutions (lOOmg/L) were prepared with TE solution (10 mM Tris-HCl, 1 mM EDTA, pH 8.00) and kept frozen. More dilute solutions of DNA were prepared with 0.05 M acetate buffer solution containing 20 mM NaCl (ABS pH 4.80) ultrapure distilled water. Other chemicals were of analytical reagent grade. 

All chemicals used were of analytical reagent grade. Deionized water was used throughout. 

AOD, 4-aminophenazone, phenol, glutaraldehyde, dialysis sacs, and aminopropyl glass beads were from Sigma (St. Louis, MO). Toyobo of Brazil donated the HRP. All other chemicals were of analytical reagent grade. 

HalHnckrodt Chemical Company, Analytical Reagent Grade copper(I) chloride, without further purification. 

The benzene used was Analytical Reagent Grade from Mallinckrodt Chemical Company, distilled through a 25-plate bubble-cap column and stored in vapor contact with desiccant prior to use. High-quality 1-hexadecylpyridinium chloride (CPC) from Hexcel Corporation was used without further purification. Sodium dodecylsulfate (SDS) was HPLC-grade chemical from Fisher Scientific Company, purified by recrystallization from an ethanol-water mixture. 

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