Real Time Analyzers (United States)

Buprenorphine is becoming the medication of choice to help patients withdraw from opioid addiction. However, treatment is compromised by the inability of physicians to assess patient usage during scheduled examinations. Here we describe the development of a point-of-care (POC) analyzer that can rapidly measure both illicit and treatment drugs in patient saliva, ideally in the physician’s office, and with a degree of accuracy similar to chromatography. The analyzer employs a relatively simple supported liquid extraction to isolate the drugs from the saliva and surface-enhanced Raman spectroscopy (SERS) to detect the drugs. The SERS-based POC analyzer was used to identify buprenorphine and opioids in saliva samples by matching library spectra to samples collected from 7 veterans. The total analysis time, including sample preparation, was ~25 minutes. Buprenorphine concentration was estimated between 0 and 3 μg/mL. While no other prescription opioids were detected in any samples, heroin was identified in one sample; Δ-9 tetrahydrocannabinol (THC) was detected in 3 samples; and acetaminophen, caffeine, and nicotine were detected in several samples, none of which interfered with the measurements. The analysis was in very good agreement with urinalysis, correctly identifying the presence or absence of buprenorphine and THC in 13 of 14 measurements.

Protection of military personnel and civilians from water supplies poisoned by chemical warfare agents (CWAs) requires an analyzer that has sufficient sensitivity (μg/L, ppb), specificity (differentiate the CWA from its hydrolysis products), and speed (less than 10 minutes) to be of value. In an effort to meet these requirements, we have been investigating the ability of surface-enhanced Raman spectroscopy (SERS) to detect cyanide and sulfur mustard in water. In our work, we have developed a novel SERS-active material that consists of a porous glass with trapped metal particles. Previously, we coated the inside walls of glass vials and measured cyanide at 1 mg/L in water in as little as 1 minute. However, measurements of sulfur mustard have only been measured to 10 mg/L. Recently, we filled glass capillaries with the SERS-active material. Here we describe measurements of cyanide, sulfur mustard, and it's hydrolysis product, thiodiglycol, using these capillaries and a portable Raman analyzer suitable for point and continuous water monitoring.

Fuel is the single most import supply during war. Consider that the US Military is employing over 25,000 vehicles during Operation Iraqi Freedom. Most fuel is obtained locally, and must be characterized to ensure proper operation of these vehicles. Determination of fuel properties is currently determined using a deployed chemical laboratory. Unfortunately, each sample requires in excess of 5 hours to characterize. To overcome this limitation, we have developed a portable fuel analyzer capable of determine 7 fuel properties that allow determining fuel usage. The analyzer uses Raman spectroscopy to measure the fuel samples without preparation in 2 minutes. The challenge, however, is that as distilled fractions of crude oil, all fuels are composed of hundreds of hydrocarbon components that boil at similar temperatures, and performance properties can not be simply correlated to a single component, and certainly not to specific Raman peaks. To meet this challenge, we measured over 500 diesel and jet fuels from around the world and used chemometrics to correlate the Raman spectra to fuel properties. Critical to the success of this approach is laser excitation at 1064 nm to avoid fluorescence interference (many fuels fluoresce) and a rugged interferometer that provides 0.1 cm^-1 wavenumber (x-axis) accuracy to guarantee accurate correlations. Here we describe the portable fuel analyzer, the chemometric models, and the successful determination of these 7 fuel properties for over 30 unknown samples provided by the US Marine Corps, US Navy, and US Army.

Extended weightlessness causes numerous deleterious changes in human physiology, including space motion sickness, cephalad fluid shifts, reduced immune response, and breakdown of muscle tissue with subsequent loss of bone mass and formation of renal stones. Furthermore, these physiological changes also influence the metabolism of drugs used by astronauts to minimize these deleterious effects. Unfortunately, the changes in human physiology in space are also reflected in drug metabolism, and current pre-flight analyses designed to set dosage are inadequate. Furthermore, current earth-based analytical laboratory methods that employ liquid or gas chromatography for separation and fluorescence or mass spectrometry for trace detection are labor intensive, slow, massive, and not cost-effective for operation in space. In an effort to overcome these instrument limitations we have been developing a sampling device to both separate these drugs and metabolites from urine, and generate surface-enhanced Raman (SER) spectra. The detailed molecular vibrational information afforded by Raman scattering allows chemical identification, while the surface-enhancement increases sensitivity by six or more orders of magnitude and allows detection of nanogram per milliliter concentrations. Generally no more than 1 milliliter of sample is required and complete analysis can be performed in 5 minutes using a portable, light-weight Raman spectrometer. Here we present the SER analysis of several drugs used by astronauts measured in synthetic urine and reconstituted urine.

Protection of military personnel and civilians from water supplies poisoned by chemical warfare agents requires an analyzer that has sufficient sensitivity (μg/L), selectivity (differentiate the warfare agents from its hydrolysis products), and speed (less than 10 minutes) to be of value. In an effort to meet these requirements, we have been investigating the ability of surface-enhanced Raman spectroscopy (SERS) to detect these chemicals in water. The expected success of SERS is based on reported detection of single molecules, the one-to-one relationship between a chemical and its Raman spectrum, and the minimal sample preparation requirements. It is equally important to detect and distinguish the hydrolysis products of these agents to eliminate false-positive responses and evaluate the extent of an attack. Previously, we reported the SER spectra of GA, GB, VX and most of their hydrolysis products, as well as a preliminary study of HD, and its principle hydrolysis product thiodiglycol. Here we expand this study to include half-mustard, its hydrolysis product, 2-hydroxyethyl ethylsulfide, and ethyl ethylsulfide to better characterize the observed SER spectra. We also report the measurement of 10 μg/L of thiodiglycol as we continue to improve sensitivity.

Pesticides are a key component in protecting crops and producing the quantity of food required by today's world population. However, since excessive concentrations pose a threat to human health, the USA sets strict tolerance levels to ensure public safety. Unfortunately, many other countries ignore these regulations and imported food exceeding these levels or contaminated with banned pesticides is a common occurrence. Furthermore, rapid chemical analysis of pesticide residues is unavailable, and only a very small fraction of foods are inspected. The greatest concern is fruit, for which an estimated 12 million tons were imported in 2003. In an effort to address this need, we have been developing a simple and rapid procedure to analyze for pesticides on fruit surfaces or in the juice of fruits. The procedure employs metal-doped sol-gel filled capillaries that both chemically extracts the pesticide and generates surface-enhanced Raman spectra when irradiated. The SERS-active capillaries, sensitivity, and preliminary fruit analyses are presented.

During the past decade Raman spectroscopy has moved out of the shadow if IR spectroscopy and has become a routine laboratory tool for chemical analysis. This is largely due to the development of stable diode lasers, fiber optic samples probes, compact optical designs, high quantum efficiency detectors, and personal computers with fast electronics, and associated data acquisition and analysis. These developments allow real-time, multi-component chemical analysis, and suggest the use of Raman spectroscopy for process monitoring and control. Single-ended fiber optic proves simplify coupling into process streams, allow remote placement of the Raman instrument from the sample point, and give Raman spectroscopy a decided advantage over IR spectroscopy in industrial liquid and solid process applications. Indeed, more than a dozen new Raman instrument companies offering fiber optic based systems have been launched in the past five years. Notably, all of these systems employ charge coupled device detectors. And yet, only one company has successfully penetrated the industrial market. Instrument limitations cited include fluorescence interference, incomplete spectral coverage, wavelength reproducibility, and long-term instrument stability. To address these limitations, Real-Time Analyzers has developed a Fourier transform Raman instrument. It employs a diode pumped Nd:YAG laser with excitation at 1064 nm and a single element, uncooled InGaAs detector, that are integrated into On-Line Technologies' proven rugged, vibration and temperature immune interferometer. Instrument design and industrial applications will be presented.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.