Mass spectrometric study of the deterioration of polystyrene-based ion-exchangers.
A mass spectrometric study of the aging effects in polystyrene-based ion-exchangers has been made. Fragments in the m/e range 10-70 were examined and attributed to OH(+), H(2)O(+), CO(+), CO(+)(2), supplemented by SO(+) and SO(+)(2) from sulphonic-acid cation-exchangers. Ion-current intensities were found to be dependent on the state of the resin.
The determination of glycollic acid in solutions previously in contact with ion-exchange resins
Abstract Two methods were examined for the determination of glycollic acid which had been in contact with polystyrene-type cation-exchange resins. For resins with high degrees of cross-linking (8% DVB or greater), a titration based on oxidation with dichromate was satisfactory but for resins with lower cross-linking, variable 'blank' values caused difficulties. A spectrophotometric method with chromotropic acid was shown to be applicable to solutions from any resin irrespective of the cross-linking, and also to the determination of glycollic acid in the presence of lactic acid if the glycollic : lactic ratio (w/w) was not less than 4:3.
Community refinement of glaucoma referrals
AbstractAim To describe a Manchester-based glaucoma referral refinement scheme designed to reduce the number of false-positive referrals to the hospital eye service. To report on the first years results of this scheme and its financial costs to the NHS.Methods Patients with suspected glaucoma, instead of being referred to their GP and then on to the hospital eye service, were referred to a group of specially trained community optometrists working to an agreed set of referral criteria. Those patients who did not meet the referral criteria were returned to the referring optometrist, while those who met the referral criteria were referred directly to Manchester Royal Eye Hospital. The patient's GP was informed in all cases.Results The number of suspect glaucoma cases referred to the Manchester Royal Eye Hospital was reduced by 40%. This figure is close to the percentage of false-positive referrals measured at Manchester Royal Eye Hospital prior to the onset of this study. The information accompanying referral has been improved and the scheme produces a small financial cost saving to the NHS of approximately £17 per patient.Conclusion Community refinement of suspect glaucoma offers some important benefits over the current referral pathway.