Gas chromatographic assay of total and O-acetyl groups in bacterial lipopolysaccharides |
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Authors: | I Fromme H Beilharz |
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Institution: | Max-Planck-Institut für Immunbiologie, 78 Freiburg i. Br., Western Germany |
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Abstract: | An improved gas chromatographic method for the determination of total, i.e., amide- and ester-linked, acetyl groups in hydrolysates of bacterial lipopolysaccharides has been developed. After hydrolysis with 0.2 n HCl overnight at 100°C and adjustment of the hydrolysate to pH 3–4, 2 μl of the samples contalning 0–6 μg of acetic and 1–2 μg of propionic acid are directly injected into a gas chromatograph fitted with a 1.5-m glass column packed with Porapak QS. O-Acetyl groups can selectively be determined after hydrolysis with 0.05 n NaOH for 3–4 hr at room temperature and adjustment of the sample to pH 3–4. N-Acetyl groups can be calculated as the difference between total and O-acetyl. The above-mentioned phase allows quantitation of short-chain volatile fatty acids (S-C VFAs) up to n-valeric acid in a range of 0–6.0 μmol using an appropriate internal standard. |
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Keywords: | Address reprint requests to Dr I Fromme Max-Planck-Institut für Immunbiologie Stübeweg 51 D-7800 Freiburg i Br West Germany |
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