Certified sulfur

Do you require suppliers to provide documentation that all piping and appurtenances are certified "for chlorine service" or "for sulfur dioxide service" by the manufacturer ... 

Glauser SC, Glauser EM Sulfur hexafluoride—a gas not certified for human use. Arch Environ Health 13 467, 1966... 

Sulfuric acid comes in different grades technical, which is colored and contains impurities but which can be used to make fertilizer, steel, and bulk chemicals certified pure (CP) and U.S. Pharmacopeia (USP). The last two are used to make batteries, rayon, dyes, and drugs. Rubber or lead-lined containers can be used for dilute acid iron, steel, or glass can be used for concentrated acid. Shipments require a white DOT label. 

In case there is a need to perform wavelength accuracy and photometric accuracy measurements for the far-UV region below 240 nm, there are new certified reference standards available from Stama Cell [18]. The wavelength standard is a solution of rare earth oxides solvated in dilute sulfuric acid. The standard exhibits well-characterized absorption bands at 210, 211, 222, 240, and 253 nm (Figure 10.13). The photometric accuracy standard consists of a series... 

You purchased a Standard Reference Material (Box 3-1) coal sample certified by the National Institute of Standards and Technology to contain 3.19 wt% sulfur. You are testing a new analytical method to see whether it can reproduce the known value. The measured values are 3.29, 3.22, 3.30, and 3.23 wt% sulfur, giving a mean of 3r = 3.260 and a standard deviation of, v = 0.04,. Does your answer agree with the known answer To find out, compute the 95% confidence interval for your answer and see if that range includes the known answer. If the known answer is not within your 95% confidence interval, then the results do not agree. 

All reactant solutions were prepared using degassed, distilled water. Fisher certified grade 1-propanol and Fisher HPLC grade 2-propanol were used as the reactants. No impurities were detected in these reagents by HPLC or GC analyses. The sulfuric acid used was a Fisher certified grade ION solution. 

FMAE was compared with pressurized-liquid, Soxhlet, and ultrasonic extraction for the analysis of sewage sludges. The optimum conditions for FMAE were determined to be 30 W, for 10 min in 30 ml of acetone HEX (1 1, v/v). Recoveries for certified reference marine sediment, CRM 1941a, were 75, 61, and 56% for FLA, B[b]F, and B[a]P, respectively. Activated copper bars were added to samples to remove sulfur. Mean recovery by FMAE was 70% compared to traditional Soxhlet extraction. FMAE recoveries exceeded those for ultrasonic extraction but better results were obtained by pressurized-liquid extraction (PEE) with the best results obtained by Soxhlet extraction. All extracts required column cleanup, concentration, and solvent exchange for RP-HPLC-FLD analysis. 

Two diesel fuels have been used. The first one was a certified fuel, Haltermaim CEC RF-03-A84, containing 0.14 wt % sulfur. The second fuel was a low sulfur fuel, obtained fi-om van Gelder Aardolie B.V., with less than 0.001 wt % sulfur. In the case that certified fuel was used, the MIPAN ammonia analyser was equipped with an SO2 scrubber. 

Many sulfur SRMs have been produced by NIST over the years that have proven to be highly useful in determining the bias and accuracy of existing and new test methods. Very recently, NIST has been preparing some ultra-low sulfur fuel standards to help the industry in coping with the analyses of such clean fuels. A partial list of such available NIST SRMs for sulfur in petroleum products is given in Table 12. There is also work underway toward certifying other low level sulfur SRMs. 

Reference materials [133] for processes described as reaction, dissolution and dilution, except for reactions carried out in combustion bombs, are also included in this section. Potassium chloride is currently used as a reference material for the enthalpy of solid-solution calorimetric determinations, and it is available as a certified material. Other recommended reference materials are tris(hydroxylmethyl)-aminomethane (secondary), 4-aminopyridine (secondary), sulfuric acid solution + sodium hydroxide solution (primary). 

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