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The Canadian FA-59 enzymatic method for determining cis,cis-methylene interrupted polyunsaturated fatty acids has been modified to meet the needs of the cholesterol and fatty acid regulations of the U.S. Food and Drug Administration. A centrifugation step has been introduced to remove palmitate and stearate interference with absorbance readings for samples containing low amounts of cis,cis-methylene interrupted polyunsaturated fatty acids. The data are calculated by using a standard curve and an equation which yields g trilinolein/100 g product rather than % linoleic acid in a given weight of sample. The standard curve was linear for 1–12 μg trilinolein. Recovery of added trilinolein was 99.5%, with 4% coefficient of variation. The modified procedure was successfully applied to a wide variety of foodstuffs.

A gas-liquid chromatographic (GLC) method, using the butyryl esters of sterols, has been developed for the measurement of cholesterol, stigmasterol, sitosterol, and campesterol in foods. An immobile phase of 1 % SE-30 coated on 100–120 mesh Gas-Chrom Q packed in a 6′ × 4 mm id glass column operated at 255°C was the most satisfactory of 7 column packings evaluated. Extraction with chloroform-methanol gave 98.7 % recovery with a coefficient of variation of 1.8% for cholesterol added to a variety of foods. When cholesteryl palmitate was added to vegetable oil and the butyryl derivative was prepared, followed by GLC analysis, the recovery was 99.3% with a coefficient of variation of 0.9%. Amounts as low as 1 mg/100 g food can be detected with a precision of 2.5%. The results of the analysis of a variety of foods for cholesterol, campesterol, sitosterol, and stigmasterol are given.

An analytical scheme, in several parts, dealing with the identification of explosives and incendiary destructive devices encountered in actual cases is described. Part I is introductory and is the first step taken in the examination of bomb debris for the various types of explosives and/or incendiaries. Examples and photographs of typical bomb residues are presented.

A collaborative study was conducted to compare the USP XVII (Emmerie-Engel) method and three GLC methods for quantitatively determining a-tocopherol, a-tocopheryl acetate, and a-tocopheryl succinate in pharmaceutical products. Nine collaborating laboratories analyzed seven pharmaceuticals encompassing tablets, capsules, and liquids. The mean coefficients of variation were: USP method, 28.6%; GLC method A, 10.2%; GLC method B, 10.8%; GLC method C, 18.0%. GLC method A was the method of choice of those evaluated. The vitamin E analogs are extracted with n-hexane from ground tablets and capsules; liquid preparations are diluted with n-hexane or injected directly onto the GLC column. The compounds are chromatographed on an 8′ × 4 mm id glass column paeked with 5% SE-30 on 100-120 mesh silanized Gas Chrom P, operated between 270-285°C, and the carrier gas flow rate adjusted so that ∝-tocopheryl acetate appears within 23-27 min. Acetic anhydride-pyridine reaction is utilized to determine whether ∝-tocopherol or ∝-tocopheryl succinate is present in a sample, since these two analogs have similar retention times. It is recommended that GLC method A be adopted as official first action.

Techniques developed for use with gas-liquid chromatography for the examination of evidence collected at the scene of suspected arson fires and firebombings are discussed. Both solvent extraction and vapor phase examinations are employed. Internal standards are used for the identification of specific components in actual samples to allow confirmation of hydrocarbon type, e.g., gasoline and kerosene. Operating parameters and solvent selection criteria are included. Results obtained from known materials and residual hydrocarbons in actual samples are compared.

A controlled study was carried out on 600 samples of various types of white and colored paper obtained from 10 different paper manufacturers with known production histories and dates. Neutron activation analysis was employed to measure the characterizing trace elemental compositions. Results indicated that (1) the papers examined were uniform with respect to their trace elemental compositions, (2) papers produced by different manufacturers are readily distinguishable qualitatively and/or quantitatively, (3) different batches of paper produced by the same manufacturer are generally qualitatively similar if produced within a short span of time (however, these specimens can be distinguished by quantitative analysis of the trace elements), and (4) different batches of paper produced by the same manufacturer at least 1 year apart are readily distinguishable qualitatively and/or quantitatively.

A collaborative study was conducted to compare the NF XII method and a GLC method for quantitatively determining menadione in pharmaceutical products. Ten collaborating laboratories analyzed 6 Pharmaceuticals encompassing tablets, capsules, and a liquid. Menadione is extracted with diethyl ether from ground tablets; slip capsules are opened and the contents are emptied into the ether along with the capsule parts. After filtration and removal of the ether, the residue is redissolved in n-hexane. The menadione sodium bisulfite injectable is transferred to a separatory funnel and extracted with chloroform and sodium hydroxide, evaporated to dryness, and redissolved in n-hexane. Menadione is chromatographed on a 6’ × 3mm id glass column packed with 1% neopentyl glycol succinate on 100–120 mesh Gas Chrom Q and operated at 135°C. The carrier gas flow is adjusted so that menadione appears within 5.5–6.5 mhi. Because of the coefficients of variation, additional study is recommended.

A collaborative study for the analysis of vitamin E in multivitamin tablets was conducted and the method was subsequently approved as official first action by the AOAC. Additional data were obtained by an extensive collaborative study sponsored by the Pharmaceutical Manufacturers Association, which verified the usefulness of GLC for the assay of α-tocopherol, α-tocopheryl acetate, and α-tocopheryI acid succinate. The mean coefficient of variation obtained from the 8 participating laboratories for duplicate samples, duplicate injections, was ±2.04, 1.75, and 2.71%, respectively. Further collaborative studies were conducted on samples of mixed tocopherol concentrate, multivitamin tablets, and multivitamin soft gelatin capsules. The mean coefficient of variation obtained from 13 collaborators was in the range of ±5%. The accumulated data demonstrate the utility of this technique for improved specificity and reliability of the analysis of vitamin E.

A chemical method for the determination of calcium pantothenate in pharmaceutical preparations is presented. The method involves a number of modifications of a method of Zappala and Simpson to make it applicable to a wide variety of materials. The pantothenate molecule is cleaved with acid, and the resultant β-alanine is treated with a chlorinating solution and then with potassium iodide. The free iodine is measured spectrophotometrically at 358 mμ. Interfering color, which cannot be eliminated by washing off the outer coating of tablets, is taken into account by the use of a sample blank. The results, obtained from many types of pharmaceutical samples, are in good agreement with the official microbiological assay. Beer's law is followed over a suitable working range, 0.25–1.50 mg.

A study of colored paints was made to determine to what extent individual paint samples can be characterized by neutron activation analysis. Approximately 300 samples of red, white, blue, and green paints from the major manufacturers in the United States were examined. It was found that paints of the same color produced by different manufacturers could be distinguished by this technique. Batch-to-batch variations between paints from the same manufacturer were observed, and it was found that in a small number of cases no differences were detected.

A chemical method for determining calcium pantothenate in pharmaceutical preparations has been studied collaboratively. The pantothenate molecule is cleaved with acid, and the resulting β-alanine is treated with a chlorinating solution and then with potassium iodide. The free iodine is measured spectrophotometrically at 358 mμ. The average coefficient of variation for all samples studied collaboratively is 8.9%. The method is recommended for adoption as official first action.

The USP XVII chemical method for the determination of folic acid is not applicable to pharmaceutical preparations containing p-aminobenzoic acid (PABA) or procaine hydrochloride (added to intertables to reduce discomfort). PABA is often present in older folic acid injectables in which a breakdown of the folic acid has occurred on long standing. A modified method is described to eliminate interference from these compounds by diazotizing the interfering material and then converting it to the corresponding phenol. The folic acid is then cleaved to form PABA, diazotized, and coupled with the Bratton-Marshall reagent. In a comparison of the two methods using known amounts of folic acid in the presence of PABA, better recovery of folic acid was achieved with the modified method than with the USP method. The application of this modification to commercial preparations is also demonstrated.

Gas-liquid chromatography has been used to quantitatively determine menadione (vitamin K3) in pharmaceuticals, using a 1% neopentyl glycol succinate column and a hydrogen flame detector. The gas chromatographic measurements compare favorably with results by the National Formulary methods on the same samples.

A comparative study was made of 2 GLC calibration methods for determining the menadione and menadione sodium bisulfite content of pharmaceuticals. One method utilizes an external standard and the second method makes use of butylated hydroxyanisole as an internal standard. Measurements were made on 8 pure solutions of known concentration of menadione and on 5 pharmaceuticals containing menadione or menadione sodium bisulfite. No significant difference was found between the results obtained by the 2 methods.