Development of latent footwear impression on porous surfaces using DL-alanine solution and 1,2-indanedione solution

A new method for obtaining the photoluminescence of footwear impression by using 1,2-indandione (1,2-IND) solution, which is a latent fingerprint-developing reagent, was studied. A binary complex of DL-alanine and 1,2-IND was prepared by spraying a DL-alanine solution and the 1,2-IND solution (an amino acid sensitive reagent) onto dry or wet origin footwear impression deposited on the surface of printed A4 paper. This binary complex reacts with the trace metal component in the footwear impression to form a ternary complex that exhibits photoluminescence. However, when 5-methylthioninhydrin (5-MTN) solution was used instead of 1,2-IND, no consistent photoluminescence was observed even under identical treatment conditions. In addition, when footwear impressions treated with DL-alanine and 1,2-IND solutions were stored under various temperature conditions (30, 40 and $50^{\circ}C$) and various humidity conditions (30 %, 40 %, 50 % and 60 % RH), the contrast between the footwear impression and the background decreased. Optimal footwear impression photoluminescence was obtained when the footwear impressions treated with DL-alanine and 1,2-IND solutions were stored at $30^{\circ}C$ and 30 % RH for 1 h. The sensitivity of the developed method was ccompared with the sensitivities of three known methods - black gelatin lifting, 2,2'-dipyridyl treatment, and 8-hydroxyquinoline treatment. The results showed that the sensitivity of the developed method was worse than that of the black gelatin lifting method but better than that of 2,2'-dipyridyl or 8-hydroxyquinoline treatment method.

DL-alanine과 1,2-indanedione을 이용한 종이에 남은 족적의 증강

잠재지문 증강시약인 1,2-indandione (1,2-IND) 용액을 사용하여 종이에 유류된 족적의 형광을 얻는 방법을 연구하였다. 인쇄물이 출력된 A4 용지에 유류된 dry origin 및 wet origin 족적에 아미노산의 일종인 DL-alanine 용액과 아미노산 검출시약인 1,2-IND 용액을 뿌려서 DL-alanine-1,2-IND 이성분착물을 만들었다. 이 이성분착물은 족적에 있는 미량의 금속성분과 반응하여 광발광을 내는 삼성분착물을 형성함으로써 족적의 형광을 관찰할 수 있었다. 그러나 1,2-IND 용액 대신 5-methylthioninhydrin (5-MTN) 용액을 이용하면 처리 조건을 동일하게 유지해도 족적의 형광이 일정하게 관찰되지 않았다. DL-alanine 용액과 1,2-IND 용액으로 처리한 족적을 다양한 온도조건 (30, 40, $50^{\circ}C$)과 다양한 습도조건 (30, 40, 50, 60 % RH)에서 보관한 결과 온도와 습도가 높을수록 족적과 바탕면의 대조비가 감소하였다. DL-alanine 용액과 1,2-IND 용액으로 처리한 족적을 $30^{\circ}C$, 30 % RH에서 1 h 동안 보관하면 족적의 최적 형광을 얻을 수 있었다. 저자들이 개발한 방법의 감도를 black gelatin lifting, 2,2'-dipyridil 용액 처리 방법, 8-hydroxyquinoline 용액 처리방법의 감도와 비교하였다. 그 결과 저자가 개발한 방법의 감도는 gelatin lifting 방법보다는 떨어졌으나 2,2'-dipyridil 용액 혹은 8-hydroxyquinoline 용액 처리방법보다는 우수하였다.