Aqueous injection

Intravenous aqueous injections provide an excellent means of achieving a rapid therapeutic response. Parenteral product design, eg, vehicle and other excipient selection, as well as choice of route of adrninistration, can prolong therapeutic activity and increase onset times. Thus, oily solutions, suspensions, or emulsions can be adrninistered by subcutaneous or intramuscular routes to create prolonged effect, ie, depot injection (28). 

Trihalomethanes. Wherever chlorine is used as a disinfectant in drinking-water treatment, trihalomethanes (THMs) generaUy are present in the finished water. The THMs usuaUy formed are trichloromethane (chloroform), bromodichloromethane, dibromochloromethane, and tribromomethane (bromoform). There are four main techniques for the analysis of THMs headspace, Hquid— Hquid extraction (Ue), adsorption—elution (purge—trap), and direct aqueous injection. The final step in each technique involves separation by gas—Hquid chromatography with a 2 mm ID coUed glass column containing 10 wt % squalene on chromosorb-W-AW (149—177 p.m (80—100 mesh)) with detection generaUy by electron capture. 

The method for chloroacetanilide soil metabolites in water determines concentrations of ethanesulfonic acid (ESA) and oxanilic acid (OXA) metabolites of alachlor, acetochlor, and metolachlor in surface water and groundwater samples by direct aqueous injection LC/MS/MS. After injection, compounds are separated by reversed-phase HPLC and introduced into the mass spectrometer with a TurboIonSpray atmospheric pressure ionization (API) interface. Using direct aqueous injection without prior SPE and/or concentration minimizes losses and greatly simplifies the analytical procedure. Standard addition experiments can be used to check for matrix effects. With multiple-reaction monitoring in the negative electrospray ionization mode, LC/MS/MS provides superior specificity and sensitivity compared with conventional liquid chromatography/mass spectrometry (LC/MS) or liquid chromatography/ultraviolet detection (LC/UV), and the need for a confirmatory method is eliminated. In summary,... 

The direct aqueous injection and LC/MS/MS muiti-residue method determines aiachior, acetochior, metoiachior and their soii metaboiites in water sampies. The accuracy of the anaiyticai method is estimated based on the recovery of known concentrations of each metaboiite fortified into controi water sampies that are then carried through the anaiyticai procedure. The method was vaiidated over the range 0.25-20 qg kg for aii components and is presented in Section 7. 

This analytical method determines levels of major oxanilate and sulfonate soil metabolites of acetochlor, alachlor, and metolachlor in groundwater and surface water. The method consists of analysis of environmental samples by direct aqueous injection reversed-phase LC/MS/MS. 

Water samples, received from the respective groundwater trials, are analyzed by direct aqueous injection (DAI) by LC/ESI-MS/MS. A 1-mL volume of the water is pipetted into a 1.8-mL autosampler vial. The internal standard solution is added (200 qL) and mixed. The vials are capped and analyzed by LC/ESI-MS/MS using the selected reaction monitoring (SRM) mode. 

Ca >ared to inorganic adsorbents these columns are stable to aqueous injections. 

Hcxanc can be determined in biological fluids and tissues and breath using a variety of analytical methods. Representative methods are summarized in Table 6-1. Most methods utilize gas chromatographic (GC) techniques for determination of -hexane. The three methods used for preparation of biological fluids and tissues for analysis are solvent extraction, direct aqueous injection, and headspace extraction. Breath samples are usually collected on adsorbent traps or in sampling bags or canisters prior to analysis by GC. 

Injection HPLC with Post Direct Aqueous Injection HPLC... 

Fujii T. 1977. Direct aqueous injection gas chromatography-mass spectrometry for analysis of organohalides in water at concentrations below the parts per billion level. J Chromatogr 139 297-302. 

Determination of Glyphosphate in Drinking Water by Direct-Aqueous Injection HPLC, Post-Column Derivatization, and Eluorescence Detection... 

Analysis of Bis(2-chloroethyl) Ether and Hydrolysis Products by Direct Aqueous Injection GC/Fourier Transform... 

Potter, T.L. Analysis of petroleum-contaminated water by GC/FID with direct aqueous injection, Groundwater Monitor. Remed, 16(2) 157-162, 1996. 

Detection limit of acrylonitrile by direct aqueous injection was 2300 J.g/L. This value believed to be a glassware contaminant. 

The exact concentrations of some of the volatile solvents in the wastewater were determined using direct aqueous injection of 2 m1 aliquots onto a 2 m x 0.32 cm ID stainless steel column packed with 0.4% Carbowax 1500 on Carbopak C (Supelco, Inc.) and analyzed by GC/MS. 

ASTM. 1988. Standard practice for measuring volatile organic matter in water by aqueous-injection gas chromatography - method D 2908-87. In 1988 annual book of ASTM standards. Vol. 11.02. Water II. Philadelphia, PA American Society for Testing and Materials, 46-51. 

Analysis of aqueous solutions of the polar compounds (DCP, TCP, CA, and DCB) at concentrations of 1-10 ppm was easily accomplished by direct aqueous injection liquid chromatography. The Hamilton PRP-1 reverse-phase column gave a better resolution of these compounds than the conventional reverse-phase columns. Acetonitrile/water mixtures have been found to be as effective as the buffered mobile phases recommended by the manufacturer (28). Analyses of the nonpolar compounds (BHC and DEHP) at concentrations of 25-100 ppb were achieved by XAD resin adsorption-desorption, concentration, and GC techniques. 

The Supelcowax 10 column has the ability to accept water injections. Direct aqueous injections of the 10-ppm standard water mix were performed to verify... 

Figure 2. GC-MS chromatogram of direct aqueous injection of the standard mixture.

Trimesic acid Diazomethane derivatization, GC-FID capillary Direct aqueous injection, HPLC (paired ion) Diazomethane derivatization, HPLC... 

The use of LC also has increased in use in recent years, driven by greater sensitivities of the detectors. Traditional ultraviolet (UV) and photo diode-array detectors were frequently employed in triazine analysis, but advances in source designs have provided efficient coupling of MS with LC. The advantage of LC is the ability to analyze polar metabolites not amenable to analysis using GC. Recent progress in LC/MS/MS instrumentation has enabled the direct aqueous injection (DAI) of a water sample without prior cleanup. 

Fuhrman, J.D. and J.M. Allan (2003). Determination of acetanilide degradates in ground and surface waters by direct aqueous injection LC/MS/MS. ACS Symposium Series. 850 256-272. 

Huang, S-B., T.J. Mayer, R.A. Yokley, and Rolando Perez (2006). Direct aqueous Injection LC-ESI/MS/MS analysis of water for atrazine, simazine, and their chlorotriazine metabolites. J. Agric. Food Chem., 54(3) 713-719. 

Munch, J.W. 1995. EPA, Method 531.1—Measurement of V-methylcarbamoyloximes and /V-mclhyl-carbamates in water by direct aqueous injection HPLC with post column derivatization, Revision 3.1. Washington, DC. 

Extractant phase None Direct aqueous injection (DAI) Static headspace with gas syringe (SHS) Dynamic headspace/ purge trap (P T)... 

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