Evaluation of the Dr?ger Alcotest model 7110 infrared breath alcohol analysing instrument

Until 1986, commercially-available infrared breath alcohol analysing instruments employed wavelengths in the region of 3.4 mu. The move to the 9.5 mu region in the Dr?ger Alcotest 7110 promised greater discrimination against endogenous compounds such as acetone. The present study confirmed that acetone interference is insignificant and that in terms of in vitro accuracy and precision, the ten 7110 units tested were superior to the Breathalyzer 900, the instruments they will replace for evidential testing in South Australia. The new unit meets the South Australian Police demand for portability and its shielding prevents interference fron any of the common radio frequency transmissions in Adelaide when operating as near to the source as possible. Comparisons of breath results (monthly averages) and their corresponding blood results accumulated during the first few months of operation showed no bias between the two techniques.