Two methods for the determination of oxalic acid were collaboratively studied. In both methods, the oxalic acid in spiked and unspiked spinach is precipitated as calcium oxalate from a buffered (pH 4.0–4.5) solution. The precipitate is separated from the solution by centrifuging 15 min at 1700 rpm. The oxalic acid is determined either by titrating the oxalate in the precipitate with potassium permanganate or measuring the calcium in the precipitate by atomic absorption and calculating it as oxalic acid. Mean recoveries of oxalic acid added at the 175 mg/100 g level were 99.5 and 100.5% for the titration and atomic absorption methods, respectively. Mean recoveries at the higher levels were 99.4% (315 mg oxalic acid added/100 g) and 97.8% (350 mg/100 g), respectively.

The development of patterned media for high density information storage requires the development of methods for cheaply creating patterns in the 20-40 nm range. Cylinderical phase block copolymers self-assemble on this length scale to give the desired patterns. However, use on noble metal capped magnetic phases of such cylinder forming phases needs a thin orienting layer to align the cylinders perpendicular to the substrate surface. Random copolymers of similar composition to the block copolymer provide an appropriate orienting layer. By attachment of a thiol group to the random co-polymer, the random copolymer will be covalently bound to a platinum or gold surface allowing the formation of a suitably thin orienting layer. Synthesis of such thiol-functionalized polystyrene-polymethylmethacrylate random co-polymers is reported. The synthesis uses a novel two-step route starting with commercially available polystyrene-polymethylmethacrylate random copolymer.

Caviar samples were spiked at the 0.1 and 0.2% levels and digested with nitric acid in a closed Teflon-lined digestion vessel to prevent volatility losses. The boron was complexed with 2-ethyl-l,3-hexanediol and extracted into methyl isobutyl ketone. The emission of the boron oxide band was measured in a nitrous oxidehydrogen flame. The mean recoveries at the 0.1 and 0.2% levels for 6 collaborators were 95.7 and 97.1%, respectively. The method has been adopted as official first action.

A method for the determination of lead extracted from glazed ceramic surfaces was adapted from the German standard procedure and extended to include extractable cadmium. Studies comparing a 0.5 hr exposure to 4% acetic acid at room temperature (22±2°C) with a 24 hr exposure under the same conditions indicated that the longer exposure gave higher, asymptotic values for extracted metal. In the collaborative study, 7 samples of the 24 hr leach solution containing lead, one of these also containing cadmium, were sent to 13 collaborators for analysis by atomic absorption. The results show that the method is precise and accurate. The average relative standard deviation for lead was 5.2%, and for cadmium, 3.9%, with average recoveries of 101% for both metals. The method has been adopted as official first action.