Proteins, nucleic acids are best example of natural polymers. Similarly cellulose is also a natural polymer which acts as main structural component of plants. Usually natural polymers are composed by condensation polymerisation with the elimination of water molecule.
Drug-Laboratory Test Interactions. False-positive urine immunoassay screening tests for phencyclidine (PCP) and amphetamine have been reported in patients taking venlafaxine. This is due to lack of specificity of the screening tests. False positive test results may be expected for several days following discontinuation of venlafaxine therapy. Confirmatory tests, such as GC/MS will clear that misconception up asap...or if you are not using pcp and your dr is sceptical.
9 Upon admission, the patientâs routine immunoassay for amphetamines showed a negative result, but after 3 days, a repeat analysis was positive for amphetamine. A confirmatory test was ordered and identified IV phenylephrine as a likely cause of the false positive.Another drug that has been associated with false positive results for amphetamine is 1,3 dimethylamylamine (DMAA). DMAA has sympathomimetic activity and is an ingredient in some dietary and weight-loss supplements. Upon admission, the patientâs routine immunoassay for amphetamines showed a negative result, but after 3 days, a repeat analysis was positive for amphetamine. A confirmatory test was ordered and identified IV phenylephrine as a likely cause of the false positive.