Determination of the Optimal Ammonium Sulfate Concentration for the Fractionation of Rabbit, Sheep, Horse, and Goat Antisera

Abstract. The performance of six custom-built Hygrocopicity-Tandem Differential Mobility Analyzers (H-TDMA) systems was investigated in the frame of an international calibration and intercomparison workshop held in Leipzig, February 2006. The goal of the workshop was to harmonize H-TDMA measurements and develop recommendations for atmospheric measurements and their data evaluation. The H-TDMA systems were compared in terms of the sizing of dry particles, relative humidity (RH) uncertainty and consistency in determination of number fractions of different hygroscopic particle groups. The experiments were performed in an air-conditioned laboratory using ammonium sulfate particles or an external mixture of ammonium sulfate and soot particles. The sizing of dry particles of the six H-TDMA systems was within 0.2 to 4.2% of the selected particle diameter depending on investigated size and individual system. With regard to RH uncertainties, the H-TDMA systems showed deviations up to 4.5% RH from the set point at RH=90% investigating the hygroscopic growth of ammonium sulfate particles and comparing the results with theory. The evaluation of number fractions investigating an externally mixed aerosol delivered differences up to +/−8% in calculated number fraction for one and the same aerosol type. We analysed the datasets of the different H-TDMAs with one fitting routine to investigate differences caused by the different data evaluation procedures. The results showed that the differences were reduced from +12/−13% to +8/−6%. We can conclude here that a common data evaluation procedure to determine the number fraction of externally mixed aerosols will improve the comparability of H-TDMA measurements. We finally recommend, to ensure a good calibration of all flow, temperature and RH sensors in the systems. It is most important to thermally insulate the RH control unit and the second DMA and to monitor those temperatures as accurately as 0.2 °C. For a correct determination of external mixtures, it is necessary to take into account size-dependent losses due to the diffusion in the pluming between the DMAs and in the aerosol humidification unit.

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Determination of Extraction Buffer and Ammonium Sulfate Percentage for Pollen Crude Protein Extracts of Mangifera, Durio and Syzygium Fruit Flowers

International Journal of Current Research and Review ◽

10.7324/ijcrr.2017.9182 ◽

2017 ◽

Keyword(s):

Ammonium Sulfate ◽

Crude Protein ◽

Extraction Buffer

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Extraction, Cleanup, and Quantitative Determination of Aflatoxins in Corn

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/63.3.631 ◽

1980 ◽

Vol 63 (3) ◽

pp. 631-633 ◽

Cited By ~ 2

Author(s):

James E Thean ◽

David R Lorenz ◽

David M Wilson ◽

Kathleen Rodgers ◽

Richard C Gueldner

Keyword(s):

High Pressure ◽

Liquid Chromatography ◽

Quantitative Determination ◽

Ammonium Sulfate ◽

Silica Gel ◽

Normal Phase ◽

Aqueous Methanol ◽

Normal Phase Hplc ◽

Water Saturated

Abstract A method is proposed for extraction and cleanup of corn samples for the quantitation of 4 aflatoxins by high pressure liquid chromatography (HPLC). After aqueous methanol extraction, ammonium sulfate treatment, and partition of aflatoxins into chloroform, sample extracts are partially purified on Sep-Pak cartridges or small columns packed with HPLC grade silica; cleanup requires only 13 mL solvent/sample. Aflatoxins B1, B2, G1, and G2 in the purified extract are resolved in ca 10 min by normal phase HPLC on a microparticulate (5 μm) silica gel column with a 50% water-saturated chloroform-cyclohexaneacetonitrile- ethanol solvent, and are measured by ultraviolet fluorescence in a silica gel-packed flowcell. Recoveries of added aflatoxins B1, B2, G1, and G2 were 84–118 % at levels of 1.5–125 μg/kg

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