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A reversed-phase high-performance liquid chromatographic method is described for the analysis of mefloquine and its carboxylic metabolite in 100-microliters capillary blood spots dried on chromatographic paper. Each spot was cut into small pieces, and mefloquine and its metabolite were eluted with an ammonia-water solution (10:90, v/v). The compounds were extracted simultaneously after alkalization at pH 9.5 using tetrabutylammonium as ion-pairing agent and then separated on a C18 column with ultraviolet detection at 227 nm. The recovery of the drugs from spiked blood applied to paper and dried was 70-80%, and the inter-assay precision at 1.0-5.0 mumol/l (therapeutic range) was less than 10%. The correlation between extractions from venous whole blood and capillary blood applied to chromatographic paper was more than 0.94. The analytes were stable in dried blood spots for at least fifty days at -20 degrees C. The decrease of concentration was less than 10%, when the paper was stored at 37 degrees C for fifty days. The assay is reliable and easy to use for therapeutic monitoring of mefloquine with a lower limit of determination of 0.3-0.5 mumol/l.

A gas chromatographic method for the determination of resin and fatty acids in sediments is described. In this procedure, the sediment sample was air-dried and soxhlet-extracted with a mixture of acetone—methanol (88:12, v/v) in the presence of hydrochloric acid. The acids extracted were converted into their pentafluorobenzyl esters and were then cleaned up on a deactivated silica gel column. Final analysis was performed on either a DB-17 or a DB-5 capillary column with electron-capture detection. Quantitative recovery was obtained from fortified sediments for all acids except palustric, neoabietic and levopimaric acids. The detection limit of all acids in this method was 0.1 μg/g based on 1 g of sample. This procedure has been successfully applied to the monitoring of resin and fatty acids in sediment samples collected in the vicinity of several Canadian pulp mill locations.

A technique has been developed for the extraction of a clean concentrate of chlorophenols from cardboard food containers and adhesives of the type used in their manufacture. A simple, reversed-phase, isocratic high-performance liquid chromatographic (HPLC) system employing an optimised mobile phase permitted the separation of nineteen different phenols. The use of a carefully selected internal standard permitted the estimation of (sub) parts per million levels of pentachlorophenol, 2,3,4,6-tetrachlorophenol and 2,4,6-trichlorophenol in several samples of adhesives and various sections of cardboard food containers. Pentachlorophenol (50 ng) and 2,4,6-trichlorophenol (20 ng) gave significant HPLC peaks, readily permitting their detection in parts per billion from 100-g samples.

Mefloquine is determined in 100-microliter samples of whole blood, plasma and capillary blood collected on filter paper by gas chromatography with electron-capture detection after derivatization with phosgene. Sample preparation for whole blood and plasma involves a protein precipitation step that uses a combination of zinc and acetonitrile, followed by simultaneous extraction with methylene chloride and derivatization with phosgene at pH 9.50. Filter paper spots are immersed for 12-24 h in 0.1 M hydrochloric acid, followed by simultaneous extraction with methyl tert.-butyl ether and derivatization. After evaporation of the organic phase and reconstitution with ethyl acetate, 1 microliter of the extract is injected into a megabore capillary column. Because of the high sensitivity of the method, mefloquine concentrations down to 25 nmol/l (9.5 micrograms/l) are determined in 100-microliters samples with a relative standard deviation of 12% at the 25 nmol/l level. Excellent precision was obtained over the range of concentrations tested, 0.10-3 mumol/l (45-1100 micrograms/l), in both plasma and whole blood and from filter-paper-collected capillary blood. The day-to-day relative standard deviation in plasma at the therapeutic level (1-3 mumol/l) was 4.5% (n = 8).

Reversed-phase high-performance liquid chromatography with UV detection is studied for the determination of both progestogenic and oestrogenic components of oral contraceptive formulations. The applicability of the assay is demonstrated for a number of different progestogen—oestrogen combinations in both conventional tablet and novel “paper” formulations. The results show that the method developed is a versatile technique for the routine assay of these pharmaceutical formulations.

Determination of chlorine and chlorine dioxide in workplace air by impinger collection and ion-chromatographic analysis

The paper chromatography of the 2,4-dinitrophenylhydrazones of the C3-13n-alkan-2-ones, the C1-14n-alkanals the C3-11,16n-alk-2-enals and the C5-12,14,16,18n-alka-2,4-dienals on six batches of acetylated paper (Schleicher & Schull 2043b/21ac) is described. With a batch obtained in 1959 excellent chromatograms were obtained by equilibration overnight with methanol saturated with “heptane” followed by descending development with “heptane” saturated with methanol. With the other five batches obtained in 1962, the separation of all compounds was also excellent but the faster moving spots tended to streak. This was prevented by equilibration with methanol alone or preferably by running the mobile solvent through a “retardation strip” of about 12 cm of a slow paper (Whatman No. 2 or No. 20) before the acetylated paper. The optimum temperature for the latter chromatograms was 30°.

Some 75 nitrogen-containing substances have been screened with regard to their interaction with blood albumin by means of crossing-paper electrophoresis. The results show that there are definite relationships between the interaction and the chemical structure of the substances. Only tertiary amines with at least one substantial radical interact, whereas primary and secondary amines and quaternary ammonium salts do not. With mixed amines interaction only occurs if the tertiary nitrogen “dominates” the other amino groups.

The relative rates of movement of amino acids are compared on ion-exchange cellulose and ion-exchange resin loaded papers under comparable conditions. The effect of changing conditions of development on the sequence of amino acids is also described.

The techniques which have been used to detect tritium on paper and thin-layer chromatograms are reviewed and their theory of operation and experimental limitations discussed. A simple technique is described whereby small amounts of tritium-labelled compounds may be detected on thin-film chromatograms.