Product Sampling

HPLC is routinely used for both qualitative and quantitative analyses of environmental, pharmaceutical, industrial, forensic, clinical, and consumer product samples. Figure 12.30 shows several representative examples. 

Liquid cycloahphatic amines and diamines have exacting purity and color standards. Almost all are sold to specification, not performance standards. Use as isocyanate precursors requites low water content criteria for these hygroscopic fluids, hence nitrogen blanketing is often specified for product sampling as well as storage and transport. 

Laboratory Information Management System. The QC lab must analy2e raw material, in-process, and finished product samples adhere to cahbration schedules record data and perform statistical analyses. These activities lend themselves to the appHcation of software packages such as a laboratory information management system (LIMS) (qv). An inexpensive LIMS is within the reach of even small laboratories. 

Whereas issues of technician productivity, sample status, and scheduling of analyses are economically important, these take second place to the issue of measurement quaUty in the laboratory. LIMS software enables activities such as cahbration and proper maintenance to be scheduled automatically. By recording the results of these activities in the LIMS, the data to demonstrate proper performance are readily made available. Additionally, the schedule can be adjusted to reflect the actual needs of the individual instmments. 

A plot of In n versus L is a straight line whose intercept is In and whose slope is —l/Gt. (For plots on base-10 log paper, the appropriate slope correc tion must be made.) Thus, from a given product sample of known shiny density and retention time it is possible to obtain the nucleation rate and growth rate for the conditions tested if the sample satisfies the assumptions of the derivation and yields a straight hne. A number of derived relations which describe the nucleation rate, size distribution, and average properties are summarized in Table 18-5. 

Crystallizers with Fines Removal In Example 3, the product was from a forced-circulation crystallizer of the MSMPR type. In many cases, the product produced by such machines is too small for commercial use therefore, a separation baffle is added within the crystallizer to permit the removal of unwanted fine crystalline material from the magma, thereby controlling the population density in the machine so as to produce a coarser ciystal product. When this is done, the product sample plots on a graph of In n versus L as shown in hne P, Fig. 18-62. The line of steepest ope, line F, represents the particle-size distribution of the fine material, and samples which show this distribution can be taken from the liquid leaving the fines-separation baffle. The product crystals have a slope of lower value, and typically there should be little or no material present smaller than Lj, the size which the baffle is designed to separate. The effective nucleation rate for the product material is the intersection of the extension of line P to zero size. 

Is there a documented procedure for retaining product samples How long ... 

The USA Military Specification (Ref 14) contains the following requirements and criteria (1) a pre-production sample must meet the Spec requirements, (2) silicon monoxide shall be of a high purity grade, (3) chemical compn as detd by the powder—D-C arc semiquantitative technique... 

Product Sample Records. Many industrial laboratories prepare samples of proposed products for customers to test. These are often not well recorded or identified. There have been many cases where it was impossible later on to say which version of a proposed product had been submitted. Every sample of this kind should carry both a date and a reference number. For the sake of simplicity, the number can be the page number from the appropriate work book. With such a system, all pertinent information regarding a sample can be quickly retrieved when needed—during a telephone discussion, for example. 

Another significant difference between large- and small-scale processing is dilution of the product samples with water. Food processing equipment for fluids often needs to be started with water, and the food needs to be flushed from the system with water before the process is shut down. When making small batch samples in this type of equipment, care must be taken to obtain a representative sample with a minimum of dilution. There will also be a difference in the weights of the sample into and out of the process due to water addition or sample loss to minimize dilution. 

Considerations in designing a market basket survey also include the period of time over which product samples will be collected. For example, should samples be collected over one year to illustrate an annualized perspective on the data of interest, or is the issue more aptly addressed with a shorter collection period such as one season or one month ... 

Is the application or system an integral part of the equipment/instrumentation used in testing, release, and/or distribution of the product/samples ... 

Can the application or system be used for product/sample recall, reconciliation, stock tracing, product history, or product-related customer complaints ... 

For each condition change, product samples were collected in regular (usually 1 hour) intervals at the output of the pressure regulator. Sampling time was adjusted to obtain about 10 g of the reaction mixture. After weighing, the sample was diluted with 50 ml iPrOH to achieve a homogeneous clear liquid. Acid content was determined by titration with NaOH solution in iPrOH using phenolphthalein as indicator. 

Considerable attention should be paid to obtaining samples truly representative of the production process early in method development. Production processes generate mixtures that are far more complex and variable than may be generally realized therefore, a separation developed using an early production sample may prove to be inadequate for a later sample. Minor peaks observed in the chromatogram, whether known or unknown, serve as a record of the consistency of the process and can be used to monitor process changes. Sometimes a particular peak can be associated with a desirable or undesirable property of the product and used for controlled process optimization. 

The laboratory should maintain the master records for all lots of incoming raw material as well as finished product. Samples should be retained by the laboratory for immediate identification or future reference, which constitutes a reserve sampling system... 

Research on pesticides in food products carried out in 1965-66 in Khersonsk Oblast (Ukraine) detected HCH in 80% of vegetable product samples, and DDT in 74.3%o (in products of animal origin, these figures were 10%o and 93.8%), respectively). The daily diet of subjects from Group I intensity work contained 2.31 mg of DDT [A77]. 

Where aqueous NMS solutions are used as the feedstock, higher NMP 2P product ratios are generally observed. However, when aqueous NMS feed is run at 265°C, free methanol is observed in the earliest product samples. Loss of the methyl group from NMS via high temperature hydrolysis apparently becomes significant at this temperature. With aqueous NMS as the feedstock, and when the reaction temperature is lowered to 200°C, NMP 2P molar product ratios as high 67 1 were observed for the more active 2.5%Rh2.5%Re/C catalyst. At the same temperature, even the less active 2.5%Rh2.5%Zr/C catalyst displayed a respectable NMP 2P product ratio of 38 1. 

Polymerization/lsomerization. The polymerization of 5-methyl-1,4-hexadiene (>99% pure) was carried out in n-pentane with a (5-TiCl3/Et2AlCl catalyst at 0°C according to the procedure described previously (14). To assess monomer disappearance and identify isomerization products, samples were withdrawn at specified intervals from the reaction mixture for GLC analysis (14). The final polymer conversion was determined by precipitation in excess methanol. 

Table 34-3 Individual sample analysis precision for hypothetical production samples...

To compute the results shown in Table 34-5 for production samples, the accuracy of each set of replicates for each sample, method, and location was individually calculated using the root mean square deviation equation as shown in equations 34-5 and 34-6 in standard symbolic and MathCad notation, respectively. The standard deviation of each set of sample replicates yields an estimate of the accuracy for each sample, for each method, and for each location. The accuracy is calculated where each y is an individual replicate measurement GM is the Grand Mean of the replicate measurements for each sample, both methods, both locations and N is the number of replicates for each sample, method, and location. The results found in Table 34-5 represent samples 1-3. Note Each sample had a Grand Mean computed by taking the mean for all measurements made for each of the samples 1-3. 

Table 34-7 Individual sample precision and accuracy for combined Methods A and B and Labs 1 and 2 - Production samples...

Both analytical methods are quite precise and accurate, therefore the production samples are below target value concentration. 

The concept of continuous flow SILP hydroformylation was also tested in the biphasic, liquid-liquid hydroformylation of 1-octene using the Rh-norbos catalyst system [78], TOFs of 44 h"1 were achieved after 3-4 h with no sign of deactivation at prolonged reaction times. At steady-state conditions an n/iso ratio of 2.6 was obtained. No leaching of rhodium metal could be detected by ICP-AES analysis of product samples at least after these short reaction times. 

The determination of an accurate product spectrum for the Fischer-Tropsch (FT) reaction is not trivial because there is not an analytical technique available to accurately quantify a product sample consisting of hydrocarbons and oxygenates... 

Near-infrared spectroscopy is quickly becoming a preferred technique for the quantitative identification of an active component within a formulated tablet. In addition, the same spectroscopic measurement can be used to determine water content since the combination band of water displays a fairly large absorption band in the near-IR. In one such study [41] the concentration of ceftazidime pentahydrate and water content in physical mixtures has been determined. Due to the ease of sample preparation, near-IR spectra were collected on 20 samples, and subsequent calibration curves were constructed for active ingredient and water content. An interesting aspect of this study was the determination that the calibration samples must be representative of the production process. When calibration curves were constructed from laboratory samples only, significant prediction errors were noted. When, however, calibration curves were constructed from laboratory and production samples, realistic prediction values were determined ( 5%). 

Figure 6.1 Overview of a generalized downstream processing procedure employed to produce a finished-product (protein) biopharmaceutical. QC also plays a prominent role in downstream processing. Qualty control personnel collect product samples during/after each stage of processing. These samples are analysed to ensure that various in-process specifications are met. In this way, the production process is tightly controlled at each stage...

Platinum electrodes 2, temperature sensor in the heat transfer medium 3, resistance thermometer 4, product sample 5, heat transfer medium 6, resistance heating. 

C Red No. 2) has been utilised by Hill2 and by Bufton and Saddlerl42 to assay neomycin in aqueous solution. Amaranth may also be used to determine neomycin in production samples from fermentation-recoveryl68. The dye, Orange II, has been similarly described(A max. = 484 nm). Complex formation between neomycin and the dye is very dependant on the ionic strength of the solution, thus necessitating careful control of reaction conditions to ensure complete precipitation of the complex during the assay procedure. Reaction of sodium 1,2-naphtho-quinone-4-sulphonate with... 

---